Caius
Note: ST stand for Single Target and AoE is for Area of Effect
Note: C65 stand for crystal level 65
What he do
BRV ATK
Melee attack - Steals enemy's BRV
Change to 2-hit ST BRV ATK+ while Body and Soul active
      Increase active Body and Soul by 1 when inflicting Break or ATKing target afflicted with Break
Change to 4-hit ST BRV ATK++ While with at least 3 levels of Body and Soul active
      Increase active Body and Soul by 1 when inflicting Break or ATKing target afflicted with Break
HP ATK
Melee attack - Expends BRV to deal HP damage
Change to 2-hit ST HP ATK+ while Body and Soul active
      ncrease active Body and Soul by 1 when inflicting Break or ATKing target afflicted with Break
Change to 3-hit ST BRV + HP ATK++ While with at least 3 levels of Body and Soul active
      Increase active Body and Soul by 1 when inflicting Break or ATKing target afflicted with Break
Skill 1  (Pulsar Burst)
Melee attack - 6-hit ST BRV + HP ATK
Buff Guardian (raises MAX BRV, ATK) and Body and Soul (Restores a certain amount of HP, BRV) to self
Change to 8-hit ST BRV + HP ATK (Pulsar Burst+) with 5 level of Body and Soul
Skill 2  (Eye of Bahamut)
Melee attack - 4-hit ST BRV + HP ATK
Deals 20% HP damage to non-targets
Increase active Body and Soul by 2, duration by 1
Debuff Poison – Chaos (Effects a certain amount of BRV damage), MAX BRV Down – Chaos (Lowers MAX BRV), DEF Down – Chaos (Lowers DEF), Doom – Chaos (Inflicts Break upon expiration) to all targets
Change to 6-hit ST BRV + HP ATK (Eye of Bahamut+) with 5 level of Body and Soul
Deals 50% HP damage to non-targets
EX+ (3/3) Skill  (Inferno)
Melee attack - 4-hit AoE BRV + HP ATK + Increase BRV by 20% of HP damage dealt + 4-hit AoE BRV + HP ATK
Deals proportionate HP damage to each target, delay target 1 turn, Knock Back to target on hit
Buff Chronic Shackles (raises INT BRV, mBRV; extends duration of buffs granted by self) and Body and Soul (Restores a certain amount of HP, BRV) to self
Change to Grant party BRV based on own mBRV + 4-hit AoE BRV + HP ATK + Increase BRV by 20% of HP damage dealt + 4-hit AoE BRV + HP ATK (Eye of Bahamut+) with 5 level of Body and Soul
Deals extra BRV damage to debuffed targets
What can he provide
Frame debuffs, delay and knock back with his EX+ skill. His Inferno+ provide BRV too. He able to self HP regen. His c65 is another 2-hit melee BRV attack + HP attack that also debuff. His C68 raises own INT BRV, ATK. He has a A sphere: Raises INT BRV, ATK by 5% while HP is MAX
What can he be
Damage dealer that can hit harder with his debuffs, delay and launch target. Don't think he can solo.
Overall thought
He is a damage dealer that can debuffs. He also has a buff call Heart of Chaos, this allows him not to die for one time. He restores his HP if HP less than 1% of MAX; Heart of Chaos then will be cancel. He cannot tag with others debuffer as he, himself has 4 debuff and it is frame