Xur'goth Boss Guide for Trial by Felfire

The boss utilises a Demon-themed deck mixed in with some cheap Warlock removal tools like Unstable Felbolt. The boss will also make use of special adventure cards such as Rusted Voidwalker and Deteriorate throughout the fight.

The deck you are provided with consists of a mix of Hunter and Rogue cards, and makes use of Secret, Beast, and Combo synergies. Additionally, you will have a copy of Shalja, Outcast dormant on your board that will become active once you have killed 4 enemy Demons.

The boss puts up very little resistance in the encounter, and as a result, you should primarily focus on finding proactive early-game cards in your mulligan. Ideally you should try to find a 1-Mana, 2-Mana, and 3-Mana card like Spymistress, Bamboozle, and SI:7 Agent.

This boss will make use of its Rusted Gaze Hero Power every turn to corrupt one of your cards, which is more of a blessing than a curse as the boss will waste 1 Mana each turn casting it. The boss will mostly target cards that you already wish to play, making its effects negligible. However, if a low-tempo card like Explosive Trap is targeted, you can often avoid playing it in favor of a more impactful card as you can easily refill your hand with The Right Tool.

For most of the fight, you should focus on controlling the board instead of rushing down the boss. This will allow you naturally to progress towards killing the 4 Demons required to free Shalja, Outcast. Once Shalja is free, you can make use of her Rush and Windfury effects to control the board while rushing down the boss with any other minions you have on board.