Adrian was basically soloing the boss if you consider his soulbounds as his personal skills. Saena even left the tanks and started healing Sirius and Kanlaon due to them being hit by attacks of the Magma Titanoboa. Adrian did not want to use Sirius' signature skill as there was still the dungeon boss that needs to be raided.
Adrian was also switching aggro with Kanlaon as they would confuse the Magma Titanoboa on who will it target first. This was very useful but Adrian would usually be the one to be attacked by the lunging skill of the Magma Titanoboa. The most important fact is that Adrian actually uses the attack of the Magma Titanoboa to attack itself thereby giving him more aggro.
The giant fire snake was basically mad at Adrian that it prioritized him for even if Kanlaon was fishing out the most damage. Just Adrian alone was whittling down its health by a lot. The other raid members could only gasp in amazement.
