"The Heresiarch can (...) Create a barrier that deflects projectiles."

"For players using Baratus (the Fighter), the Heresiarch can be hard to kill because he can only be hurt while his barrier is down."

"Note that the Heresiarch with the deflecting shield up will still be damaged by any melee weapons, including the fighter's axe (...) He's not that invincible really, it's only an anti-missile shield. "

Okay, so what's the truth? Can you hurt a shielded Heresiarch with the fighter's melee weapons or not? JudgeDeadd 16:53, 29 December 2013 (UTC)

I'll try to dig into the code and confirm which damage types are allowed to get through the Heresiarch's invulnerability; unfortunately this stuff is just haphazardly hard-coded all over the Hexen executable so it's easy to miss - and in some cases even, misinterpret - the code responsible. To make it worse plenty of code in Hexen doesn't even do what it's obviously meant to do by the developers, due to subtle issues they didn't catch and which even skilled programmers can overlook when reading the code - it's a nightmare, in other words. --Quasar 15:34, 30 December 2013 (UTC)
In my (non-source-code-based) knowledge, no melee attack can hit through shields, nor can the Sapphire Wand (it will pass through, but not cause damage). Melee attacks and the wand are, however, safer since they won't bounce back (although the Serpent Staff gets reflected even if used at melee range). I believe that the only weapons that will damage through shielding are gas clouds (as from mushrooms or the Cleric fléchette) and the Arc of Death. However, this depends on whether the Heresiarch shield works the same way as the Centaur's does. I think it does, but I'm not 100% certain. ETTiNGRiNDER 18:32, 9 January 2014 (UTC)
I have verified in the source code that the only inflictors that are excepted from the invincibility granted by Hexen's MF2_INVULNERABLE flag are MT_POISONCLOUD (whether spawned by a Cleric's flechette or a mushroom), MT_FIREBOMB (the Mage's exploding flechette), and MT_HOLY_FX (the ghosts from the Wraithverge). Now, out of THOSE three, only the first two can damage the Heresiarch while his shield is active because in PIT_CheckThing, the latter will be reflected before it does any damage due to the Heresiarch also possessing the MF2_REFLECTIVE flag. There are no exceptions granted to tracer-based or direct-damage melee attacks. So basically, the Fighter is out of luck with a complete inability to penetrate the Heresiarch's defense, while the other two classes can cheap-strat him by planting a bunch of flechettes on top of him while he's standing still doing his long spell casting animation. --Quasar 15:34, 19 January 2014 (UTC)
Interesting. Is there a special exception for centaurs/slaughtaurs that makes them vulnerable to the arc of death, then? -- ETTiNGRiNDER 15:41, 19 January 2014 (UTC)
While invulnerable, no, not that I can find. It does do more damage to them when they're NOT invulnerable, however:
					if(thing->type == MT_CENTAUR 
					|| thing->type == MT_CENTAURLEADER)
					{ // Lightning does more damage to centaurs
						P_DamageMobj(thing, tmthing, tmthing->target, 9);
						P_DamageMobj(thing, tmthing, tmthing->target, 3);

--Quasar 16:07, 19 January 2014 (UTC)

The propensity for it to prevent them from becoming invulnerable, btw, is due to the lightning setting things it damages into their painstate with a chance of 96/256. This means that Centaurs and Slaughtaurs will be repeatedly prevented from fully bringing up their shield. So from that POV, you could say they are more vulnerable to it in general. It takes a Centaur 6 tics to bring up his shield, but lightning can deal damage every tic. --Quasar 16:17, 19 January 2014 (UTC)