When Soul Warden enters the battlefield, Warstorm Surge triggers, dealing 1 damage to you.
Darien triggers, creating a 1/1 Soldier creature tokens.
When the Soldier enters the battlefield, Warstorm Surge and Soul Warden trigger.
Resolve the Soul Warden trigger, causing you to gain 1 life.
Resolve the Warstorm Surge trigger, dealing 1 damage to you.
Repeat from step 3.
This loop is a masterclass in self-sustaining synergy, anchored by Warstorm Surge to turn every new arrival into a source of self-inflicted damage. That damage immediately rouses Darien, King of Kjeldor to muster a 1/1 white Soldier token in response, which in turn triggers Warstorm Surge anew to deal yet another point of damage back to you. Meanwhile, Soul Warden quietly cushions the blow by granting you 1 life with every single creature that enters the battlefield, offsetting the damage and letting you sustain this infinite loop of tokens, lifegain, and triggers indefinitely.