The Fire Elemental can trigger a fiery aura that will cause fire damage to Geralt if he remains too close for a long time.
In addition, the Elemental can dish out some nasty close range melee attacks and will frequently chalk the ground causing a place of effect shockwave if you stay too close.
He also has ranged abilities with and may also take out a wave of passion in a line right facing him as well as tossing fireballs that can burst on impact resulting in a little splash damage if you are too near them.
The fight is tough for one reason, the awkward surroundings makes it hard to approach the boss without him being able to attack first.
Whilst he sounds hard, he is actually not really that catchy to take down. Employing AARD will temporarily eliminate his fiery aura; disabling his fire-based AOE crush and letting you pretty much treat him as a normal large enemy.
YRDEN can also be helpful in that it will slow him down to make him more manageable. Once he’s in the weakened state, we’ll have to await an opening in its own strikes.
Luckily most of its attacks are quite obviously telegraphed and there is a small window following any attack he can.

