Ember excels in the magical manipulation of energy and matter. This lends an intrinsic affinity for illusions, which are just magically manipulated light through various means.

This permits him to perform "reasonable processes" with physical substances, which would include things like creating fire, freezing water, etc-- but also with more complicated processes. He does not and cannot for instance, transform lead into gold. He can, however, turn rust back into iron, and vise-versa.

Specifically, he specializes in the manipulation of non-living substances. (He is not suited for doing any kind of magical restoration or curative work.)

In addition to being a master of material manipulation, he has a sub specialty in magical compulsions. (with emphasis on geas type magic centering on seduction.)

He is proficient in other forms of magic, but it is not his preferred avenue of magical discipline. He "Can" perform incantation, but it is not something he particularly likes doing. (In fact, he dislikes it.)

He is an evoker type sorcerer, and has a direct affinity for magic itself. For him, using magic is a bit like splashing in a pool. If you pay attention you can feel the water swirl and swish with the blowing of the wind. In a similar way, if you stop flailing about, and feel gently, you can feel the ripples and eddies of magic being used around you. 

Again, much like splashing in a pool, you can make small waves and splashes with just your arms, but to REALLY make a splash, you need something to stir the water up with.  For that purpose, he requires an object to do the stirring.  Such an object needs to be of strong emotional/sentimental value, and deeply connected with the practitioner, in order to be used as a conduit for the needed intent.  It functions both like a lighting rod, and as a firehose, so to speak.  Depending on the degree of emotional attachment, and the materials from which it is fashioned, such objects may permit either only a small to modest increase in the ability to stir up the magic permeating everything-- or knock down buildings with it.

The one Ember is carrying is a momento from his college days. A friend got it for him as a gag gift (It is shaped like the "Pansexual symbol", where the closed part of the "P" is the handle guard), but it actually suited him (being over the top, garish, and whimsical), and to his (and his friend's) great surprise, it "actually works".  It is not particularly powerful, but it is more than adequate for everyday, ordinary use.  As a bit of whimsy, he brought it with him for his vacation, rather than bringing something more powerful. He jokes that the P, stands for "Pretty, Proud, and Powerful"

It is composed of rather cheap, gimmicky materials, (potmetal and rhinestones) and thus cannot handle strong magical forces being channeled through it, but it DOES have a very strong sentimental connection.  For anyone else, the wand probably would hinder, rather than improve, magical practice. This very fact, is ironically, one of the reasons it serves him so well-- He made it a point to use it, for the pure whimsy and audaciousness it conveyed his entire senior year, to the consternation of his instructors. (a memory he greatly cherishes)

In terms of raw ability, ember is a prodigy. However, his preferred means of using magic-- directly, in such a fashion-- greatly limits his abilities without proper tools.

With proper tools, he could pretty effortlessly destroy the entire ship on a whim.