A player in my home game asked about gods, and joked about the next player being forced to play a cleric. I don't think about religion a lot, and for some reason gods are real boring to me; I'm trying to make them interesting, though! I've got at least 2 others to write up. They probably won't be this lengthy or complicated.
Image by Bill Sienkiewicz from here
Shen-Drath's holy symbol is half human face, half bloody skull. The entire symbol is used, even by factions that worship one half over the other. Divisions within the church have emerged over arguments about how many arms the god has - those who favor Shen claim two, those who favor Drath claim many, many more - that he slices off the arms of foes in battle and attaches them as his own.
There is also disagreement as to whether Shen-Drath is a specific being that ascended to godhood through mighty deeds of war in ancient times, or whether the name is a kind of title. Believers of the latter say the mightiest warrior in the land can rise to become the god through a great ritual during which he survives burning away all the flesh on half of his body. A mortal is compelled to undertake this ritual when he or she reaches a level of martial prowess the other gods feel inappropriate for a mortal. Whether born of old or made anew, all agree he is the best military strategist and most bloodthirsty berserker in the land.
Casually worshipped by: Generals, politicians during war, some soldiers and berserkers
Seriously worshipped by: Soldiers, mercenaries, war priests, tacticians, some berserkers and generals
Worshippers favoring Shen must follow orders, know their rank, carry out agreements and treaties, and treat prisoners of war well. Surender and retreat are acceptable if they are the optimal strategy for the situation.
Clerics favoring Shen have the normal armor and weapon choices of the Cleric class.
Worshippers favoring Drath must never retreat, take prisoners during combat, surrender, or spare a foe.
Clerics favoring Drath or the deity as a whole may use any weapon, but may not wear armor greater than Chain Mail.
Paladins who worship Shen-Drath can not cure diseases or radiate Protection From Evil as other Paladins do.
Clerics may choose to Turn or Command Undead at the time of Turning.
-A History of Violence: The player of a Cleric or Paladin of Shen-Drath may keep a list of all the foes his or her PC has faced in battle; when facing a foe of the same type or from the same area again, the PC intuits some useful knowledge about their strategy, level of sophistication, or something else useful about fighting them. ("The orc tribes of Morath always attack in groups of 3." "Goblins in this area use stone weapons, which easily break." "Pirates from the isles of Neverbottom always ram ships from starboard." [Can you tell I'm not a military type? I hope you get the idea anyway. It should be potentially relevant or useful, but not give the fight away.])
-The Many Arms of War*: At levels 3, 6, 9, and 12, Clerics of Shen-Drath may forgo one of their spells to gain the following ability: during battle, if the Cleric can sever the arm of an animate foe, he or she may attach that arm and command it as if it were one of his/her own. This arm may make weapon attacks, aid in defense, hold items, or anything an arm can do. The foe must be alive or animate at the time the arm is severed; if severing the arm kills the foe, the arm will still work. At the end of the battle, the arm falls off and decays. (IE one arm at level 3, two at 6, etc.)
Paladins who worship Shen-Drath gain The Many Arms of War at 3rd level and may use as many arms as half their level, rounded down.
-Drath's Fury: By covering their face with the removed face, skull, blood, or viscera of a fallen foe, a Paladin or Cleric of Shen-Drath may enter a battle frenzy. During this frenzy, they gain temporary HP and bonus to hit and damage equal to half their level, rounded up. Their AC takes a penalty of 2 in this state and does not benefit from Dexterity bonuses. They must choose one enemy and attack that enemy until it is down, then will move on to the closest creature to attack next. If this is an ally, the Paladin or Cleric may make a saving thrown VS Spell aided by any Wisdom bonus to skip over them for the next nearest creature. If the saving throw fails, the frenzy has overtaken their senses and the ally is attacked until unconscious or dead.
A Paladin may not Lay On Hands the same day they have entered Drath's Fury. A Cleric must give up one spell that day to use this ability (which is gained back as normal at rest).
Shen-Drath's manifestation is 30' tall and appears as one half man, the other half bloody and skeletal - made up of the bodies of mighty warriors and high priests of the past. One arm of any creatures falling in a battle with Shen-Drath will fly to him and defend him, or attack his foes, falling to dust after the battle is over. Shen-Drath carries a mighty battle-axe that he throws unerringly and has hideous laughter. His laughter can Paralyze whether he wants it to or not, but he will not attack helpless foes.
Shen-Drath is part of the Celestial Order, Gods who enforce universal constants, organize to determine rules of reality and enforce restrictions on their priesthoods and those of others. He wants to be the God of Death, and thus both hates and lusts for Derketa. He occasionally schemes to have her deposed or destroyed, but has not been successful. Shen-Drath is respected and considered useful by other Gods; Derketa is feared and beloved.
AC: -4 or 24, HP 400, No of Attacks: 1d4+number of creatures killed so far in combat, First attack 10-100 DMG, second and others 10-40+16; Abilities of a 15th level Cleric and 20th Level Paladin; Laughter causes Paralysis on a failed save.