Alright, I'll admit that I am being slightly vague here. In all honestly, I want to highlight some points before I go on (I won't be making a character immediately as this is still in concept phase)

[indent]1.a I want the 'powerset' to be free form so that each roleplayer may play a unique set of abilities that they personally enjoy. No one has to follow a similar trend, nor do they have to create an umbrella theme. If someone just wants to manipulate the element of fire, they can.

1.b Everyone will have a standard set of abilities they can train. Strength, speed, energy project, etc.; even entire fighting styles might be fabricated, by me, or inserted into the roleplay to continuously sculpt characters in unique ways. With that said, choosing a power might be more about making a more linear path for it; for example, if someone choose to control fire, as they grew more powerful and trained, they might understand that they do not control 'fire' as much as they control combustion and become even more adept when using the concepts of combustion, space-confinement, etc. with combination with their abilities. Do keep in mind this will have science fantasy elements, so draw from both science and your imagination.

2. When I compared this to a game, I didn't mean you had to have completely set-in-stone abilities. In fact, I somewhat dislike that concept. However, it is an option and you can easily have an umbrella ability that sprouts several smaller branch abilities that are unique to themselves.

3. You are more than welcome to making your character initially ignorant to what their abilities are. In fact, I would much prefer that your characters didn't fully understand their abilities quickly. Just because a character starts off with manipulating fire doesn't mean that is his true ability. You might go a very, very long time into the RP without the true nature of your ability being known. Maybe never. Zenpachi from Bleach never knew his Bankai, and he was still fucking awesome.

4. I stress that you should plan to start slow and start relatively weak, so when considering your abilities and their reflections of your(self) character, imagine abilities that are each small expressions of such but also part of a bigger idea. You are more than the sum of your parts, but each part is still important.[/indent]

With those main points made, I found a character from a Naruto RP I was once in that should identify the concept of ability core and branches that I mean.

[hider=Hayato Nakamura][center][i]"My life changed when I began to understand... knowledge is power."[/i][/center]

[b]Name[/b] Hayato [i]"Allure of Ame [b]/[/b] Allure"[/i] Nakamura
[b]Age[/b] 32 | [b]Gender[/b] Male
[b]Alliance[/b] Konohagakure
[b]Rank[/b] Jounin
[b]Position[/b] Cursed Seal Hunter
[b]Favorite Food[/b] Fresh Shrimp
[b]Least Favorite Food[/b] Spinach 
[b]Favorite Phrase[/b] [i]"Knowledge is power."[/i]
[b]Hobby[/b] Playing musical instruments
[b]Traits[/b] High stamina, large chakra pools

[center][b]Appearance[/b]
[img]http://fc07.deviantart.net/fs38/f/2008/352/8/6/Anime_boy_by_BloodZaphir.jpg[/img][/center]
Hayato stands a solid six feet tall with a muscular frame. His auburn hair is often left completely unchecked and he has a disdain for the uniform that most shinobi at and above chuunin level are urged to wear, thus he doesn't. The only equipment that Hayato does choose to wear is a belt full of shorter-than-average scrolls accompanied by three on his back all roughly two feet in length and three inches thick. These scrolls account for a vast majority of his actual weaponry, but not all. Hayato is fit with three specialized air tubes in his arms, similar to those used by [url=http://naruto.wikia.com/wiki/Zaku_Abumi]Zaku Abumi[/url]. Aside from these characteristics, Hayato is generally defined as an 'aesthetically pleasing' man by those around him, thus earning him the nickname "The Allure of Ame" as he also originates from Amegakure.

[center][youtube]Ji-msGoqVhA[/youtube][/center]

[b]History[/b] Hayato was a prodigious chuunin in Amegakure during the Second Great Shinobi war, making his name using the enhancements given to him through Amegakure weapons specialist of the era. Due to alliances and trade unions, Amegakure had become very powerful and wealthy despite its small size, and its shinobi were receiving some of the benefits. Before the procedures, Hayato was just another genin that went into the ranks for the glory, as much of the able-bodied youth of that time did, but his ability to handle the enhancements earned him recognition. Those who received the implants in their arms often rejected them, causing damage to muscles groups and the nervous systems located in their arms, permanently lowering their combat capabilities. Hayato was able to receive three without complication, and could use them skillfully.

Hayato fought for Amegakure in the Second Great Shinobi War, but fled to Sunagakure upon the overthrow of its government, as did several other shinobi whom sought refuge. Hayato became part of a refugee culture within Sunagakure and hid within its walls and sand-struck boundary until it was finally overtaken by Sai in his last act of world domination. The Kazekage of Sunagakure held out, alongside his personal guard, until their chakra was completely exhausted and the sands shifted in the favor of Sai. This took years, however, since Sai did not truly own every country until his sixth year in power. Even with Sunagakure taken, miles of desert and hundreds of oasis provided sanctuary for most of the rogue shinobi, thus leading them, and Hayato, to the life of a wandering nomad.

During his time in Sunagakure, Hayato trained among many of the shinobi that took refuse there. He honed his Wind Release, but moreover found he had an advanced chakra nature: Sound Release. Hayato began to play instruments, learn of how sound worked, how the air worked, and as he did pushed his abilities using knowledge instead of raw power, although he did not lack the latter. This lead Hayato develop his signature fighting style by incorporating the abilities of the famous puppeteers of Sunagakure with the addition of chakra strings. Hayato spent nearly a decade honing his style as a desert nomad with those he traveled with, moving by day and playing by night.

This lasted until the resistance called upon all shinobi to take stand and rise against Sai's Empire within their domain, and Hayato was not one to ignore the horn of battle. With hundreds of nomadic shinobi alongside him, Hayato assisted in the siege of the great desert fortress of Sungakure and brought down the Sai that ran the sandy cornerstone of the world. After the fall of Sai, Hayato took to hunting those with the Cursed Marks, but with political pressure, was forced to choose sides between Sunagakure and Konohagakure. As did many shinobi, although fewer of the nomadic desert shinobi, he chose to join Konohagakure solely on the influence of the resistance and his former friends that also joined. Not long after taking a permanent spot in Konohagakure, Hayato and his loose adherence to rules, skill in frivolity using instruments and latent charm earned him the nickname "The Allure of Ame", which results in most either calling him Allure or Hayato, generally pending on gender.

[b]Personality[/b] Hayato was once a very stern shinobi that took little pride in his ability to use his implants. However, a decade spent in the desert, dancing 'round fires while honing his skills against friends led to him becoming a fairly frivolous individual. Some claim that if Hayato trained as diligently as even a chuunin, he may be just as powerful as the Hokage and Jounin Commander, to which Hayato generally retorts with apathy. Hayato prefers the foods, sensations and freedom of not being stuck in endless sand and even after months of being inside Konohagakure he truly has yet to lose interest in his frivolity. That said, Hayato does take his job quite seriously, and on a mission there is no one more focused on hunting down those with the Cursed Mark of Sai, but it is a rarity for such a mission or even lead to arise.

[b]Nature Release[/b] Wind, Sound
[b]Important Items[/b] Twelve short-scrolls that contain folded, hollow, holed metal balls. Three large scrolls on his back, each summoning a different item:

[list][*]Two large curved walls that act as barriers and sound amplifiers[/*]
[*]One harp made of material that amplifies chakra flow[/*]
[*]Sixteen large, hollow pillars of holed metal[/*][/list]

[b]Combat Style:[/b] Hayato is easily the definition of versatility when it comes to combat. Although he has no outstanding skill in taijutsu alone, Hayato has developed a nintaijutsu that works in collaboration with one of his core jutsu. Hayato has a set of core jutsu in addition to several more peripheral jutsu granting him a high level of versatility. Additionally, his years within the Sunagakure desert have left him with a high amount of stamina and his years practicing the same jutsu have granted him well-trained chakra reservers. Hayato centers his justu around the little metal balls he can summon, which is why he carries twelve scrolls. They are connected in a network of chakra that allow them to emit sound and are controlled by Hayato himself via chakra threads normally used by puppeteers. These balls can be used to enhance or alter his jutsu as well as can be enhanced with the use of his dome or pillars. Hayato is also skilled with Wind Release, although most Wind Release techniques can dampen his Sound Release, but is still capable of blasting powerful gusts of wind, if need be.

[b]Justu List[/b] All Academy Jutsu.

[u]Canon jutsu[/u]

[list][*][url=http://naruto.wikia.com/wiki/Decapitating_Airwaves]Decapitating Airwaves[/url][/*]
[*][url=http://naruto.wikia.com/wiki/Extreme_Decapitating_Airwaves]Extreme Decapitating Airwaves[/url][/*]
[*][url=http://naruto.wikia.com/wiki/Wind_Release:_Great_Breakthrough]Wind Release: Great Breakthrough[/url][/*]
[/list]
[u]Custom Jutsu[/u]

[b]Jutsu Name:[/b] Wind Release: Tempest Rising
[b]Jutsu Type:[/b] Offensive
[b]Effective Range:[/b] Close-Mid
[b]Nature Type:[/b] Wind
[b]Descriptions:[/b] Hayato performs a single handsign that conjures a wall of wind around him, acting as a barrier. This wind can be turned into a cyclone and aimed at a target with great destructive force.
[b]Drawbacks:[/b] Hayato cannot visibly see past the wind barrier when created.

[b]Jutsu Name:[/b] Helix Airwaves
[b]Jutsu Type:[/b] Offensive
[b]Effective Range:[/b] Mid
[b]Nature Type:[/b] Wind
[b]Descriptions:[/b] Using the implants in his arms, Hayato blasts compressed wind in the shape of a helix. This blast is more compressed than his decapitating airwaves, thus has greater penetrating power.
[b]Drawbacks:[/b] Hayato cannot perform handsigns while using this jutsu.

[b]Jutsu Name:[/b] Spherical Airwaves
[b]Jutsu Type:[/b] Offensive
[b]Effective Range:[/b] Mid-Long
[b]Nature Type:[/b] Wind
[b]Descriptions:[/b] This jutsu allows the creation of 'pellets' of compressed air that can be fired at high rates similar to a Gatling gun. Upon impact, the airwaves explode with a large sum of force. These pellets can be held and added together to create larger spheres that can be fired at shorter distances and slower velocities to do exponentially more collateral damage.
[b]Drawbacks:[/b] Hayato cannot perform handsigns while using this jutsu.

[b]Jutsu Name:[/b] Sound Release: Decapitating Soundwaves
[b]Jutsu Type:[/b] Offensive
[b]Effective Range:[/b] Close-Mid-Short
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Hayato creates sound waves using the three implants in his arm and manipulates them with chakra as to control their concentration, range, frequency and potency. Hayato can thusly create soundwaves that act as regular Decapitating Airwaves, Helix Airwaves or Spherical Airwaves with the use of one jutsu, and can be amplified by other sound-based jutsu.
[b]Drawbacks:[/b] Hayato cannot perform handsigns while using this jutsu.

[b]Jutsu Name:[/b] Sound Release: White Noise Zone
[b]Jutsu Type:[/b] Supplementary
[b]Effective Range:[/b] 15 meter radius
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Using the metal balls he can summon and chakra threads, Hayato creates an area that is constantly amplified by sound that is under his control, ranging from frequency, wavelength and potency. Each ball is connected with 12 chakra threads that repair in 2 seconds if cut. Each connection, aside from the outer most layer,is thus connected to twelve other balls. The constant sonic emission allows Hayato to see everything in the area in ultrasound and amplify his Sound jutsu.
[b]Drawbacks:[/b] Alone, this jutsu is effortless to maintain, but using it to amplify jutsu can be exhausting.

[b]Jutsu Name:[/b] Sound Release: White Noise Death Zone
[b]Jutsu Type:[/b] Supplementary, Offensive
[b]Effective Range:[/b] 50 meters in a do-decagon
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Hayato creates a do-decagon using the pillars he has sealed on his back that connect to the metal balls, allowing him to have far more of them in an area. These pillars channel his chakra at a higher efficiency, thus reducing their chakra use while also increasing the demand. In addition to increasing the range that Hayato can use the White Noise Zone, it also amplifies the chakra that passes through it greatly. Using sound waves alone, Hayato can deal blows to opponents as hard as regular punches, interrupt regular breathing, redirect airflow and increase pressure on a person as well as create high-pitch sounds that can deafen opponents, all within his field.
[b]Drawbacks:[/b] This jutsu requires at least four pillars to remain up to maintain, but loses some strength if any of its pillars are lost in general. This is why there are four extra in his seal.

[b]Jutsu Name:[/b] Sound Release: White jacket Insanity
[b]Jutsu Type:[/b] Nintaijutsu
[b]Effective Range:[/b] Short-Mid
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Hayato coats his body in a layer of sound-attuned chakra, then can transition his body through a White Noise Zone at just under the speed of sound itself. If there are at least four pillars standing while this jutsu is in use, Hayato can also amplify simple blows with sound-wave explosions to add collateral damage. This jutsu also protects Hayato from certain concussive forces.
[b]Drawbacks:[/b] This jutsu prevents Hayato from using other jutsu while in movement, but not while active.

[b]Jutsu Name:[/b] Sound Release: The Bell Tolls
[b]Jutsu Type:[/b] Supplementary, Offensive
[b]Effective Range:[/b] Short-Mid,-Long
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Hayato can amplify any sound wave within his White Noise Zone, including those of his own jutsu. Thus, Hayato can simply pour more chakra into his pillars and thus his jutsu to make them stronger. 
[b]Drawbacks:[/b] The chakra required to amplify jutsu.

[b]Jutsu Name:[/b] Summoning: Walls of Sound
[b]Jutsu Type:[/b] Offensive, Defensive
[b]Effective Range:[/b] Short-Mid-Long
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Hayato can summon his large, curved walls to either be used offensively or defensively. Defensively, they are simply large walls of steel, but offensively they are curved to amplify soundwaves greatly, allowing Hayato to destroy small towns with them if he was not interrupted. 
[b]Drawbacks:[/b] The specific shape of these walls can interrupt the White Noise Zone, thus forcing Hayato to only use one at a time.

[b]Jutsu Name:[/b] Sound Release: Harp of Discord
[b]Jutsu Type:[/b] Offensive
[b]Effective Range:[/b] Mid-Long
[b]Nature Type:[/b] Sound
[b]Descriptions:[/b] Hayato can use his summoned harp to conduct a symphony of destruction. Each chakra-enhanced stroke of the fingers will cause a torrent of powerful sound waves of beautific nature that can rip apart even solid steel. This jutsu grows more powerful the longer a song is played and can be made even more destructive by the use of Hayato's walls of sound. If allowed to play an entire song on his harp, Hayato could leave a village in ruin.
[b]Drawbacks:[/b] Hayato cannot miss a note, elsewise will cancel the jutsu. He must also remain stationary and he does not always have full control over the direction of the sound waves. It is possible, while using the Wall of Sound, for Hayato to be hit and even killed by his own sound wave. This jutsu was created by accident by Hayato and is one he considers a mistake.[/hider]

Admittedly, that is a slightly extreme example and it follows the setup used for ninjutsu by Naruto, but it should definitely highlight what I mean by following a theme. Additionally, these characters will be HIGHLY prone to development if this roleplay goes as I imagine, so don't begin believing the image you have is how it will turn out. I don't like it when people have a static idea and just force it. Interact. Grow. Develop. Bounce back and forth with the roleplay and your fellow roleplayers. Change your character and adjust to the interaction. You might go in a completely different direction than you begin in and ultimately add huge layers of depth. This will have fantasy elements lined within it and you will be venturing from world to world, so just because people use "Ley" doesn't mean that they won't be using mana or fel energy or the mysteries of the arcane or shamanistic mysticism. You might find a whole new branch and learn from it. Maybe become a Wizard for a while, or a Warlock, a Priest, a Spellblade or Dashing Rogue with a magical lute. I'm obviously stretching this out, and that's to make the point. You are making people like you and me, regular humans from the regular world. They will be going into new, fantastical places and your initial plan might not at all be applicable.