Timing

[miloboy]

1.If supernova / tidal wave
was used

and a lot of allies die (their attachment too.)

what is their order in graveyard (important for shadow knight)?

2.If 2 effects trigger at the same time like

Serena Thoughtripper
and
Night Prowler

who decide which one go first ?

[Mojumbo]

Heya,

To answer these questions we will use the standard resolution order (SRO).

1. According to the SRO, allies that die at the same time via the effect of Tidal Wave/Supernova/etc will be sent to the graveyard in the order they were played. For example, if you summoned Jasmine first and Aldon second, then when your opponent plays Tidal Wave the Jasmine will be sent to the graveyard first followed by Aldon second.

2. According to the SRO, hero abilities trigger and resolve before items. As such, Serena's ability will resolve first followed by Night Prowler. For example, if your opponent had 1 card in hand and you attacked with Serena while her ability was activated with a Night Prowler on the field, the card would be discarded as opposed to added to your hand.

Hope that helps