When Viktor attacks and plays Siphon Power at his first opportunity, which is then Denied, who has the next opportunity to play an Action? Does it matter if a triggered ability triggered when attacking?

Ruling: After Viktor's Siphon Power is Denied and resolves, priority passes to Ahri since Viktor had priority on the previous chain.

Nuances:

• Viktor can cast Siphon Power in response to Ahri's legend trigger
• When attacking with Recruits, it's often better to wait and cast Siphon Power in response to Ahri's trigger rather than immediately, because Ahri's reduction only procs once - if a unit is already at 1 ATK from the reduction, then gets pumped by Siphon Power, it stays pumped for the turn
• If Siphon Power is cast before Ahri's reduction applies, Recruits would go from 2 ATK to 1 ATK (from Ahri) and stay at 1 ATK