The Titans share a small arena and use a handful of attacks. Most damage is avoidable, so a solo player mainly faces a longer fight rather than a harder one.
Ranged accuracy boost: Despite Eldric's very high ranged defence of +700, you get a hidden +500% (6x) ranged accuracy whenever he is out of melee distance, lasting until he turns to re-engage in melee. This boost also applies for the entirety of the Elemental Blast, including its charge-up. So melee him when he is close, and switch to ranged the moment he backs off.
Stomp: A melee attack hitting the three rows in front of the Titan, dealing up to 26 damage. Block it with Protect from Melee. Used while in melee distance in phase 1, and across the whole arena in phase 2.
Fire / Icicle Walls: A row of fire or icicles forms over four ticks, blocking that row. Standing on a targeted tile deals up to 12 damage but stops the wall forming. Walls are destroyed by their opposing element — douse fires with Water Blast or greater (ice spells also work) and melt icicles with Fire Blast or greater — with no attack delay regardless of magic bonus.
Fire / Ice elementals: The Titans summon three elementals that attack with melee and, if left alive, self-destruct for 8-10 damage in a 3x3 area. With +70 magic attack bonus (or +39 with full void mage) your fire/water spell is a guaranteed hit, striking a 3x3 area; elementals take double damage from their opposing element. Each elemental you kill grants a 1-tick reduction to your attack delay.
Elemental Blast: Used once the fight reaches phase 2. The Titans blast the whole area with their element three times, leaving one safe tile, dealing up to 30 damage per blast.