Click on the character's name to go straight to their Dissidia Database entry in JP, to get all their info about what their abilities and equipment do, as well as other metadata.
April
Beatrix (
Steiner): Beatrix does solid Lighting Magic Damage and can protect the party with defensive and Hp Regen buffs, special ability to protect everyone's HP for one turn with a single-use HP+++ Transformation every time she uses her EX, very awesome. (Steiner does more damage. Not exciting or major, but a fun character nonetheless.)
Exdeath (
Gilgamesh): Exdeath has a massive focus on Gravity effects, basically reducing Brv by percentages before doing big attacks. He also inflicts a unique debuff, Curse, which does Hp Damage each enemy turn, as well as Debuff stats. He basically debuffs and deals tons of damage, and focuses on being able to reduce Brv without interacting with enemy Defense or Breaking enemies, which makes him very useful to party members with Breaking mechanics, like Lighting, who need to break to do extra turns and such. Very Rad! (Gilgamesh does more damage, not terribly exciting, but he has a fun kit where his abilities morph around, so that's fun.)
General
Leo (
Galuf): Okay, this is a big banner! Leo's big deal is that he's a support DPS, who provides a crucial debuff that we have technically gotten early with Aranea. It's a Framed Debuff (can't be ovrwritten or pushed off until it expires) that makes single target attacks deal 50% more damage. It's freaking rediculous, and his other attack delays enemies by two turns and does massive damage. He's a super support and is very very meta. (Galuf is no slouch either, he protects his allies from harm with Cover, and gives himself full physical [both Melee and Ranged] Evasion, and does a powerful counterattack when he dodges. He's basically like edge, except he protects the party more frequently and for much longer, but is still damaged by Magic attacks without countering them. Still very powerful, and his new EX does tons of damage as well. Very worth pulling for both!)
Vayne Solidor (Paladin
Cecil Harvey): HOOOO BOY, have I been waiting for this one! Vayne is a DPS with a twist. He may not deal a huge amount of damage on his own, but he builds stacks to a special buff that, when full, gives him three turns in a row, two being free. It's DEVASTATING when used appropriately, and that's not even his best trait! One of his abilities unbreaks an enemy, and then goes on to hit four more times, and is very powerful, while also acting as a delay attack due to how breaks work. His EX is super loaded too, as not only does it bring his stacks to full, but also gives him ability uses back for both his abilities, meaning with proper use of his good Brv+ and Hp+, he can go indefinitely and deal tons of damage! Now it also rebreaks enemies, and does more damage, his kit is loaded, and he is handsome, get immediately! (Cecil is a very useful support DPS who can fill the Battery and Healing roles in a party just fine, and now can provide both Light resist down with his EX, but also Light Enchant for the party with his AA, so he can even provide very good damage buffing in bursts. Very solid party member!)
Fran (
Ashelia B'nargan Dalmasca): Fran is a solid Damage Support, But is also now a rediculous Damage dealer too, both having a stacking debuff with tons of useful mitigating effects, as well as providing Range Resist Down, But also has a super powerful EX, and very VERY high overflow and hits on all attacks. Super powerful, very solid. (Ashe deals small debuffs on enemies, but also provides both of the rare Phys attack up and Mag attack up buffs to the party. Might make for too many buffs with other supports, but is a solid character with splash damage on her EX.)