Demonologist (3.5e Prestige Class)

Summary::A demonologist study demons and use their power to further their own gains. Minimum Level::4 Class Ability::Arcane Spellcasting Class Ability Progression::Full

Demonologist
"Calling demons 'fickle creatures' is like calling a bonfire 'warm', those who consort with them play with fire. Demonologist aren't just playing with fire, they play with fire and oil."

Demonologist are expert of demons (usually focusing on Tanar'ri) and how to control them. Despite their specialization, demonologist are not needed to be servant of demonkind, in fact a lot of lawful evil demonologist serve devils as expert at fighting and controlling demonkind. Very very rarely a demonologist is good, seeking to use the power of demons against them, which rarely end well for anyone involved.

Class Features
All of the following are class features of the Demonologist.

You do not, however, gain any other benefit a character of that class would have gained. If you had more than one arcane spellcasting class before becoming a demonologist, you must decide to which class to add each level for the purpose of determining spells per day, caster level, and spells known.

 : A 1st level demonology know a lot about demonkind, she gain a +4 bonus on all skill check when interaction with demons (including researching them with the knowledge skills). She also gain a +2 bonus to attack and +2d6 to all damage rolls against demons and other chaotic evil outsiders.

A demonologist add the following spell to her spell list (at the same level a wizard or a cleric would get them) and to her spell known at the appropriated level if applicable: summon monster I, summon monster II, summon monster III, summon monster IV, summon monster V, summon monster VI, summon monster VII, summon monster VIII, summon monster IX, persistent summon monster, planar ally, planar ally, greater, planar ally, Lesser, planar binding, planar binding, greater, planar binding, lesser.

Your fiendish companion gain benefits as if it was a animal companion using your character level as druid level for the purpose of determining benefits. If your have a familiar you may combine both abilities, granting familiars to your fiendish companion.

If the demonologist is neutral evil or lawful evil she may gain an imp instead of a quasit.

 : A 2nd level demonologist is capable of getting some loyalty when dealing with demon.... just kidding, they may however force them to go through deal by performing ritual which replicate the effect of binding contract. She may perform this ability at will, however only with chaotic or evil outsiders (despite it name).

 : A 2nd level demonologist is quite adept at binding powerful outsider in her service. The normal HD limit for your planar ally and planar binding spells (including lesser and greater versions) increases by 1 for the purpose of summoning chaotic evil outsiders and when she casts a summon monster spell, it is treated as the equivalent spell of two levels higher for purposes of summoning chaotic evil creatures.

At 5th level this ability improve further, increasing both both bonuses by 1 (+2 to maximum HD and summoning spell 3 level higher).

At 8th level this ability improve further, increasing both both bonuses by 1 again (+3 to maximum HD and summoning spell 4 level higher).

 : A 3rd level demonologist understand how to increase the power of her destructive magic, whenever she deal damage with one of her spell or spell-like ability she may make half of it pure 'abyssal' damage, thus not subject to damage reduction or energy resistance and immunity.

Upon completing the pact the demonologist effectively become fiendmarked except the entity do not always work against the demonologist (it in fact reluctant to do so unless the demonologist actively work against it interest). For the purpose of the invocation, the fiend caster level is equal to the demonologist's character level and use the demonologist own's charisma for DCs. The demojn is also capable of using a single insidious suggestion on the demonologist per day, however if it caught doing so (by succeeding both will save) it relinquish it hour of control for the day (see below).

Additionally the fiend is allowed to take possession of the demonologist for a full hour per day (decided when this ability is used), the demon-possessed demonologist use the same statistic as the regular demonologist. It come under the DM's control (or another willing player) and will not attempt to have it vessel severely damaged, compromised or killed. It will not waste the demonologist's spells unless it has good reason (self defense), it will instead typically use this time to experience the human world in a way that fit the particular fiend.

The fiend will gladly start hampering the demonologist if she attempt to screw him over and will often have demand, while it will not hamper the demonologist if she don't meet it every demand after a while it may be tempted to use it fiendmarked's abilities. The demon and the demonologist are capable of communication telepathically at any time. If the demonologist is killed in a way that release the fiend, it will typically attempt to get revenge. The fiend CR is typically equal to the demonologist's character level.

In exchange for all that hassle the demonologist gain a +2 bonus on her caster level, she gain the attune domain feat for both the corrupt and evil domains and she gain demon traits. If the demonologist is a warlock she gain two extra invocations of each invocation level she can use instead of attune domain. If she somehow expel or suppress the pact she immediately lose these benefits until she resume her pact or make another.

 : Whenever a 4th level demonologist use a summon monster spell to summon one or more chaotic evil-aligned creatures, you summon one extra creature of the same kind.

However failure is still 'discouraged', the demonologist return sickened for 24 hours after being raised or resurrected, as she is now tormented upon death even more than most as an encouragement.

If the demonologist does not have the dark-pact bound template she simply do not lose a level anymore upon death.

 : Whenever a 5th level demonologist damage a good or lawful creature with one of her spell that creature must make a will save (in addition to any save granted by the spell) or be nauseated for 1 round.

 : At 7th level a demonologist may as a 1 round action you may attempt to enslave a chaotic evil outsider to your will as per dominate monster without the [mind-affecting] tag, however it only last for 1 hour and the subject become immune to further demonbind attempts for 24 hours  wether or not it succeeded or failed it save.

Additionally you may cast binding a supernatural ability once per day, however you may only target chaotic evil outsiders.