Скачать или смотреть HSR - Version 3.8 - Event - Remnants of Twilight - Day 5 - Elegy Siren - SS Rank

Rule
If You hit the Boss (Elegy Siren) 5 Times, it will let you choose your unit and transform it into Mini Siren and fast forward to that unit Turn
In Mini Siren form your unit cannot be Heal or Shield and can only choose Explode (Normal Attack Button) and use skill to Debuff Enemy unit (Skill Attack Button)
Explode will Debuff Enemy and transform back to human form but the Skill will debuff enemy with HP% Reduce (Main Source of Damage in this mode)
If Elegy Siren Boss is Dead the Match is over
If you want all 3 Stars, you need to manage your Mini Siren well enough and not let Mini Siren force transform to Human form by HP below 0 more than 1 Times

Trick
Bring Kafka to Speed up the Damage
Bring Sustain Unit
Bring Fastforward Unit like Sunday, Bronya
Use Mini Siren Skill when you can use your Fast Forward Unit after Mini Siren Turn or before 2 Enemy Unit
If Your Mini Siren is before 3 Enemy Turn without our Fast Forward unit Explode it to make Sure.

Timestamp
Easy Mode - Trial Charater - 00:26
Hard Mode - Trial Charater - 02:23
Nightmare Mode - Limited 5 Stars E0S0 - 07:19
Character Status - 07:58