Newest SSR is fire Freyr. Gifs also uploaded.

Huh, neat; her first passive lets her build up to 200 burst gauge. Her second passive is alter stats depending on her form, which her 3rd (out of 4!) ability changes (Warrior->Saber->Lancer->back to Warrior).
Abi1 is damage + 30% fire resist debuff on 6 turn cooldown; eats 50 burst gauge. 40 burst gauge for the + version.
Abi2 is +30 burst gauage and combo attack buff for 3 turns on 7 turn cd. +40 burst gauge for the + version.
Abi4 is eat 200 burst gauge->enjoy the effects of all 3 forms for 5 turns; 15 turn cd.

Warrior's basically +damage stuff at the expense of some combo atk rate
Saber's +combo atk rate at the expense of burst gauge increase rate
Lancer's +burst gauge increase rate at the expense of some power