I'm just realising

Tank? Pffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff.

Only normies are building Shiro as a tank.
If you're not a normie then try the build below.

Tank... AHAHAHAH.
(Btw this is all a joke. Please don't hate me or I'll cry for sure.)

Well, I like a skill like close def more. Or a breath skill.
Since his speed and res aren't terrible (like Lukas has) Shiro is able to take a dragon hit and avoid doubles.

Lukas might make a bit better use out of it, given his biggest weakness from physical foes is a special proc.

And of course there's Xander.