Egniol Diet II is a grandmaster combat achievement which requires the player to kill the Corrupted Hunllef without making an egniol potion within The Corrupted Gauntlet.
This achievement can be easily completed by not leaving offensive prayers constantly on during the fight. Either flash them or do not use them.
It is not necessary to flash defensive prayers. However, it is advisable to flash prayers when fighting the demi-bosses to preserve some prayer points. Avoid spending run energy unnecessarily during the preparation phase and fight. If you have time remaining before entering the central chamber, wait out this time to replenish any missing run energy. If possible, walk during the first few lightning attacks, as it will be more valuable to have run energy during the later stages of the fight.