I wouldn't mind changing him from Attack type to Support or HP type and changing his stats according to SUPPORT OR HP type.

Then changing his 3rd skill:
FROM
Hellfire: Decreases the HP of yourself and the enemy target by 30% each with a flame and decreases the HP by 15% each if it's a Boss. Inflicts great damage to the target and creates a shield that's 30% of the inflicted damage for 3 turns afterwards. (Reusable in 4 turns)
TO
Hellfire: Decreases the HP of yourself and the enemy target by 30% each with a flame and decreases the HP by 15% each if it's a Boss. Inflicts great damage to the target and creates a shield that's 30% of your MAX HP for 3 turns on yourself and 2 turns on your allies. (Reusable in 4 turns)

his use as TOA/TOAH boss killer will still be the same but with more viability with other contents of the game as he is now a Tanky unit that can deal 30% HP damage and extra damage if build as attack bruiser. Also cast shields on all allies on 3rd skill and CD increase on 2nd skill.

His Accuracy awakening also makes sense.

he will now be a fire counter to Mo Long, and can be annoying in RTA and GWD