In Challenge Mode there is an extra phase added to the fight. The first and second phases are similar to that of normal mode but Vindicta hits much harder and her life points are increased to 300,000. Her increased damage makes it impractical to use Soul Split even during the first unmounted part of the fight. Gorvek's dragonfire attack will also hit much harder, doing around 1500 per tick and can quickly kill a player if they do not move away quickly enough. Vindicta will mount Gorvek upon reaching half (150,000) LP and Gorvek's ranged attack can hit as high as 6000+, so it is highly recommended to use Protect/Deflect Ranged to mitigate the damage, especially when coupled with Devotion, Debilitate, or Resonance.
Unlike in normal mode, depleting Vindicta's health does not complete the fight. Upon defeating mounted Vindicta, Gorvek will emerge with 300,000 LP (making the boss effectively 600,000 LP). Gorvek will use the dragonfire special very frequently like mounted Vindicta but he will only attack with melee. However, Gorvek attacks at speed of 2 ticks (1.2 seconds), making his damage per second output extremely high. It is highly recommended to use high level magic armour and perhaps a shield or defender as well. The Revenge ability is highly effective during this phase due to Gorvek's high attack speed. Frequent use of damage mitigating defensive abilities is recommended.