In short:
The Warder, a 3rd party class for Pathfinder, focuses on debuffing foes. Just like a 4e defender, he can mark enemies and those enemies take huge penalties to their attacks against other allies.
Yet, what happens is that the enemies focus on me and our Medic can't keep up with the healing.
How should I play this character to be effective and avoid dying?
More details
We started playing at level 8 and we have WBL-compliant money, which I invested in a +2 full plate, a +2 heavy shield, a +1 ring of protection and a +1 necklace of natural armor, for a total AC of 27. Most of my other money went into a +2 longsword and a strength-boosting belt (in retrospect, I think I should have bought a constitution belt, but with a +15 to hit I'm pretty weak in that compartment too. A barbarian, for comparison, would have about a +20 at the same level).
Basically, except for a dex bonus, I have all the AC I could reasonably get without nerfing my offensive capabilities, or so I think.
I'm trying the vanilla Warder, no archetypes, human (18 10 14 16 10 10 or something like that). I need to check where my favored class bonuses went for my character sheet is at our DM's but I'm pretty sure they become extra HP. Still, with +2 Con modifier, I'm at around 80 HP (we use average HP and a 22pts point buy).
The rest of the party is:
- a lizardfolk Luchador Brawler with 6 attacks per round
- a duergar Aegis with even worse to hit than me, but 100 HP and DR 7
- a dwarven Medic (yes, I know, the constant bickering with the duergar might be a bigger problem than my AC)
- an half-elf Zealot with curses
- an half-drow Stalker
- that Magus archetype that uses firearms and deals lots of damage but only every other round
I know, lots of tanky characters here (I said "I'll be the tank" while the other two people who ened up being an Aegin and a Zealot weren't there. We didn't expect someone else to want to be the tank.)
In the game where my character died we were the Medic, the Aegis, the Magus and me, against a huge advanced bulette with AC30 (which we hit on a 15 or more unless we flanked - the medic enchanted our weapons with an extra +2 when flanking and I was using the level 3 Golden Lion stance for easier flanks - as long as I was up, and with a 18 otherwise), DR, fire resistance and a lot of HP (and some archetype that let it breathe a line of lightning once, but that wasn't the problem) and combat reflexes (i.e. eat your OAs or let me pounce on you).
I used a counter to use intimidate (+20) instead of AC but it only saved me from a single attack of the bulette. Not enough to live for a second turn.