Gaurda Hard Mode

[Sephirah]

5100 HP is enough to tank Titan. I did it at 4900 on my first kill. The important part is to have a cooldown up for EVERY SINGLE MOUNTAIN BUSTER. It requires careful juggling of your cooldowns, but trust me once you get a hang of it, it makes the fight almost trivial on your end.

Just echoing this, with my food buff I was at 4995 hp my first titan kill. It's ALL about managing your cooldowns around mountain buster.