Can't beat it. Sebastian's phase is too tough and always locks onto me, leaving me with no health to deal with Elisa's final phase.
Finally beat it (phew!). Sebastian's phase is kinda evil, I find myself pressing 3 to skip the last part of it as he almost never misses. Phase 1 is too easy but I suppose that's the point of a noble not taking you seriously. I will say, the animations and story of this update are exquisite, especially the 1 friendship star ending.