Inis
Can I play a Triskel the moment an effect gives it to me?
Yes, if its trigger is met at that moment. A Triskel you just received (stolen with Raid, taken with Cove, or received through Deirdre's Beauty) is in your hand and playable like any other. The designer treats Bard stolen by Raid as having the same after-maneuver timing as Raid and Warlord.