Help with Horizon Walker Shadar Kai

[Peldrigal]

Hello, as per title, I am kind of stuck with a Horizon Walker Shadar Kai. It's a Planescape Campaign and the DM has built parts of the campaign around the availability of this character.
The problem is that the rest of the party is an Inquisitive, a Mastermind, and an Abjurator Fighter-Wizard who sort of tanks, but its tankyness will decrease as he levels up.

Any suggestions about builds and multiclassing to improve survivability and reliable damage output, given the constraints of Race and one of the classes? We are pretty flexibile with tweaking the characters for the first few levels, so nothing apart those two things is set in stone.

[awaken_D_M_golem]

(noticed the giantitp thread = legit)

Fighter 1 / Wiz Abj X ... and a small discussion about recharging the hp pool, get a Familiar.
Mastermind and Inquisitor should discuss not stepping on each others toes, partitioning the skills.
http://www.enworld.org/forum/showthread.php?488616-GUIDE-I-Fought-the-Law-and-Won-The-Rogue-Guide&p=6895455&viewfull=1#post6895455
May I suggest Inquisitor dipping Cleric Arcane 1 at level 5 for Booming Blade, and
Mastermind dipping Hexblade Warlock 2 for artillery and sneakyness (maybe at level 4 or 5).

You really need your DM to allow the UA Revised Ranger
plus a solid hint at the most typical monsters. 
Because you're gonna be the Frontliner of the party like it or not. 
Sword + Board and Dueling is your best bet early.
The Wiz can be slightly tank-ier early on, but not later.
You might be the stealth guy if the Mastermind goes Face.
Tell the Wiz to train their Familiar to shove a Goodberry
down the throat of downed party mates, otherwise
no in combat healing, no as in nada, as in my deities won't allow etc.