Chronicles of Alexstrasza appears to be a specific fan-made or indie project (likely using Unreal Engine 4) rather than a mainstream title. Because of its nature, detailed documentation is limited primarily to community-driven resources. Game Overview & Walkthrough

Part 2: The Molten Span – Bridge of Fire

After clearing the eggs, return to Caelestrasz. He will die from his wounds (scripted event) but gives you a Key Fragment (Left). Your new objective: Cross the Molten Span to reach the Twilight Hammer camp.

Mulligan for Alexstrasza’s Champion and Red Whelp (1/2 with “Battlecry: Deal 1 damage”).
Do not play minions with 1 health. They’re free refreshes for his Hero Power.
Use Lifebinder’s Scales on a high-attack minion to create an unbreakable wall. Zul’jin has no hard removal outside of minion combat.
Key turn: On turn 6, he will play Zul’jin (the spell-battlecry one). Save a Silence or Transform effect for his spawned Frothing Berserker.
Win by attrition: heal every turn, and let his own Berserker Rage wear down his minions.

The Protector (Tank): Focus on the "Iron Scales" tree. This increases your armor rating and allows you to shrug off physical debuffs. 5. End-Game: The Battle for Azeroth's Future The final act takes place at the Seat of the Aspects. Final Boss Strategy: The boss has three phases. Phase 1: Focus on the adds (minions) first.

Chronicles Of Alexstrasza Walkthrough [better]

Part 2: The Molten Span – Bridge of Fire

Mulligan for Alexstrasza’s Champion and Red Whelp (1/2 with “Battlecry: Deal 1 damage”).
Do not play minions with 1 health. They’re free refreshes for his Hero Power.
Use Lifebinder’s Scales on a high-attack minion to create an unbreakable wall. Zul’jin has no hard removal outside of minion combat.
Key turn: On turn 6, he will play Zul’jin (the spell-battlecry one). Save a Silence or Transform effect for his spawned Frothing Berserker.
Win by attrition: heal every turn, and let his own Berserker Rage wear down his minions.