taking down Titan as tank

[Nyalia]

Nah, story mode only has Landslide, Weight of the Land, and Granite Gaol. No bombs. ^^

Oh, well, then you should watch out for Granite Gaol, which petrifies a party member and prevents them from doing anything until it's broken. If you are able to, target the Gaol and throw Tomahawks at it (or, if the Gaol happens to be in melee range of the boss, melee the heck out of it - just don't turn Titan to face the party while doing so). This is especially important for you to do if one of the DPS has already fallen off the platform (which, by itself, is not necessarily a wipe), as a significant portion of your party is unable to act until it's broken.

I wonder if Tempered Will/Hallowed Ground would save you (since those prevent Landslide from knocking you back).

I haven't tested it, but I'd be very surprised if Tempered Will didn't work. It seems to prevent all abilities that move you involuntarily. Hmm, thinking about it, I wonder if it also prevents jump pads from working, or the water spouts in Hullbreaker. Ah well, things to test when I get the opportunity! Because science!