Okay, so I’m going to go through this as Grey and I did for each character. 

Now first and foremost, each character would need a reason to be in the Vongola. Why did they choose Cyril over other branch mafia families. Why Kurune when she is essentially a civvie. And why is Ari with them? Why does she know about mafia stuff? In the cases of Kurune and Cyril we could easily work out relationships with Yoshi that would serve this purpose.

More individually:
[b]Kurune[/b]([@Kyouki]) - Essentially, I like Kurune’s aesthetic. She is a good character with a lot of potential. Still, I have a few questions. How does her weaponry and skills play into her overall character? She seems to be fit for espionage or something not directly melee. I think in this case it may be necessary to focus her up a little bit. She was a civilian before, essentially just a normal person, so this is especially important. You can always enhance her skill set and equipment a little later. For instance, mist doesn’t feel like it plays a big a role in her character as it should. It doesn’t seem to compliment her character. We could also use a bit more clarification on the application of her skills, abilities, or weaponry, why she chose to focus on those, etc. 

[b]Cyril[/b]([@Ambra]) - Cyril is pretty much okay and there isn’t anything inherently off about him other than the redundant weaponry. He has a Kusarigama. He doesn’t really need the chain/knife at this point. I mean if you wanna just keep the knife as a side weapon, it could work. We also need to work more on his relationship (as well has his famiglia’s) to the Vongola as a whole, not just Yoshi. We can try to work on that together if you draw a blank, I’ve already brainstormed simple stuff. 

[b]Ari[/b] -  For Ari, the biggest thing is essentially the why she would be brought in as a combatant and member when she isn’t a guardian. She should fit a bit more naturally into the group. Her character might benefit from a bit of focusing up in the combat department as well. You don’t necessarily need to remove anything depending on what changes you may make to her. There is a lot of freedom that comes with her because she is more a side character. 
[u]Side note:[/u] Ambra… Is like Ari trying to be like Yoshi with them there gauntlets fam?? Cause he was reppin that first. Lol she cute tryin to get on his good side tho xD

[b]Mist[/b] - I’m sure I don’t [i]need[/i] to write this, but I will anyway. I’m trusting you guys not to abuse the power of mist. Apart from that, there seems to be a bit of overlap between Kurune and Ari. I feel that after looking them over and a little editing they could be a bit better differentiated. By the end, it should be clear why Kurune’s skills or talent would have her chosen as the Mist guardian.