After Siren's 10th turn or after she has been brought under 81% HP, she will shift permanently to Phase 2 Form.

After Siren's 20th turn or after she has been brought under 41% HP, she will shift permanently to Phase 3 Form.

After Siren's 30th turn, she will shift permanently to Overtime Form.

Siren will abort any currently casting ability when she shifts form.

For all abilities, Siren uses a slightly faster cast time of 1.2s in all Phases.

美女のボスはイジョハヤの法則未だに継続してるのな
メリュジーヌ然り、ユウナレスカ然り
アルティミシアも原作だがクソ早かった記憶あるわ