Yes.
The template lists all weaknesses of Vampires:
Weaknesses: Vampires cannot tolerate the strong odor of garlic and will not enter an area laced with it. Similarly, they recoil from mirrors or strongly presented holy symbols. These things don't harm the vampire—they merely keep it at bay. A recoiling vampire must stay at least 5 feet away from the mirror or holy symbol and cannot touch or make melee attacks against that creature. Holding a vampire at bay takes a standard action. After 1 round, a vampire can overcome its revulsion of the object and function normally each round it makes a DC 25 Will save.
Vampires cannot enter a private home or dwelling unless invited in by someone with the authority to do so.
[...] (exposure) to direct sunlight, [...] immersion in running water, [...] wooden stake through [the] heart [...]
Assuming your temple is not laced with garlic and is not a private home (or inside a private home), the most troublesome part are holy symbols.
Seeing that it takes a standard action to repel a vampire using a holy symbol, "strongly presented" seems to refer solely to characters or NPCs "strongly presenting" their holy symbol, as in the description of Channel Energy:
A cleric must be able to present her holy symbol to use this ability.
Arguably though, holy symbols in a temple are "strongly presented", they are usually central to the whole design (think of crosses in christian churches).
(Personally, I'd rule the latter case, because I don't like the idea of vampires walking in the front door of a Sarenrae temple, but commoner with a carved holy symbol can repel him...)
In any case, the weakness does not pertain to unholy symbols, so your bad guy is good to go.
Typical area spells found in evil temples of doom also don't hinder vampires. In fact, a vampire benefits from desecrate the same way all undead do. Unhallow also has no special effect that prevents a vampire from entering. As Jeor Mattan points out, not even hallow can prevent Vampires from walking in the front door.
Yes, but it's very unlikely.
Trying to hit a specific location on a creature requires the variant rules for called shots (Ultimate Combat p.193). Which even specify how they interact with vampires and cyclopses.
A called shot is an attack aimed at a particular part of the body, in the hope of gaining some extra effect from the attack. The smaller or better guarded the area, the more difficult the called shot. A called shot is a single attack made as a full-round action, and thus can’t be combined with a charge, feats like Vital Strike, or multiple attacks with a full-attack action.
Some effects in the game, like true strike or the flash of insight ability of cyclopes, provide automatic or nearly automatic hits. Using such an ability on a called shot turns it into a normal attack, with none of the benefits or penalties associated with called shots. From a story perspective, this is because the effect cannot distinguish between a hit in general and a hit in a particular area, but it’s also necessary to keep the power of such abilities in line with their original intended effects. Some Game Masters may prefer a more theatrical or dangerous game in which magic can make a shot through the eye nearly certain, in which case this rule can be ignored.
The consequences of a successful called shot vary depending on whether the hit is a normal hit, a critical hit, or a debilitating blow (a hit that deals half the creature’s hit points of damage (minimum 50) or more).
Heart
Called shots to the heart are challenging (–10 penalty).
Called Shot: A called shot to the heart is just a normal hit with no extra effect.
Critical Called Shot: [...] A critical hit to the heart against a vampire made with a piercing weapon composed entirely of wood leaves the vampire impaled through the heart by the weapon if it fails its Fortitude save, with effects as described in the vampire monster details.
Debilitating Blow: [...] A debilitating blow to the heart against a vampire made with a piercing weapon made entirely of wood affects the vampire as a critical hit to the heart; for example, it still receives a Fortitude save to avoid the consequences.
So it's theoretically possible, but you have to pass all of the following criteria:
- Perform a single attack as a full-round action. (Unless you've taken a feat to relax this constraint.)
- Hit while taking -10 to the attack roll, and without using Flash of Insight or anything else that would trivialize this step.
- Either get a critical hit or deal at least 50 damage or half the vampire's hp (whichever is higher).
- And finally the vampire gets a fort save. (DC = the numeric result of your attack roll, i.e. the highest AC it could have hit).
Best Answer
Note: This answer is for dnd-3.5e exclusively. Other answers may provide pathfinder specific advice.
The Monster Manual on Slaying a Vampire says, "Exposing any vampire to direct sunlight disorients it: It can take only a single move action or attack action and is destroyed utterly in the next round if it cannot escape" (253). Libris Mortis expands on this description, that text on Sunlight Vulnerability saying that this means
That text's Table 7–3: Undead and Sunlight (ibid.) says that sunlight exposure leaves a vampire "disoriented, destroyed" then provides a note saying, "One round after exposure to sunlight begins, a vampire that remains exposed is destroyed utterly." However, the Monster Manual remains the primary source for a vampire, and that means—despite Libris Mortis—during that 1 round the vampire still exists after it's exposed to sunlight—when the vampire's disoriented—a vampire is still limited to only either a move action or a standard attack. This limitation on the vampire's actions makes it incredibly difficult for a vampire to activate effects that can rescue a vampire from its impending destruction.
For example, even if a DM were to allow the effect to function in such a way—and most won't, making that an incredibly big if—, blotting out that pesky sun via the effect of the Iron Heart maneuver iron heart surge [special] (Tome of Battle 68) is impossible for the typical disoriented vampire as such a vampire must take a standard action to employ the maneuver. Further, for example,—assuming the rules for doing so from the Rules Compendium are in use (85)—activating a wand of quickened no light [trans] (Book of Vile Darkness 100) (0-level spell at caster level 1 modified to a 4th-level slot by a level 7 caster) (420 gp/charge) is also impossible, a disoriented vampire being unable to take even free actions, much less a swift or immediate action.
With all this in mind, for a vampire on a budget, listed below are what I think are the most cost effective ways for a dnd-3.5e vampire to avoid destruction from exposure to direct sunlight.
Wear clothing that "covers the body completely"…
If the DM's hewing closely to the rules, an explorer's outfit (PH 129, 131) (10 gp; 8 lbs.) probably won't be enough to cover the vampire's body completely, so a cold weather outfit (PH 129, 131) (8 gp; 7 lbs.) likely won't be enough either. A vampire in such a campaign needs an outfit that says it covers the wearer from head to toe, face included. The black bodysuit (Arms and Equipment Guide 29, 30) (30 gp; 1 lb.) may be sufficient, although to reap its other benefits also the vampire must be lightly equipped. However, the most foolproof method of covering everything according to the rules is probably the hydration suit (Sandstorm 99, 101) (1,000 gp; 10 lbs.), essentially a Dune-style stillsuit with goggles and everything (from the novels not the films). However, a more generous DM could rule an explorer's outfit sufficient, maybe supplemented with piecemeal clothing from the Arms and Equipment Guide's Table 2–2: Clothing (29).
However, for a vampire, the terrifying thing about relying on this method to protect it from a sunlit environment is that clothing—like other worn items besides armor—is vulnerable to sunder attempts… and sundering a worn object is particularly easy: not only is doing so usually easier than hitting the vampire, but also clothing typically doesn't have much in the way of hardness or hp. Seriously, once a dnd-3.5e vampire that's out in the open on a sunny day is recognized as a vampire, the good folks of the town should do their best to rip its clothes off.
…Then take the feat Endure Sunlight…
The monstrous feat Endure Sunlight (LM 26) has as its prerequisite a vulnerability or weakness to sunlight—like that of the typical vampire—and has as the following benefit :
This gives any vampire at least 1 round to do something other than move or attack, like activate a wand of obscuring mist [conj] (PH 258) (1st-level spell at caster level 1) (15 gp/charge) (just as effective as the 2nd-level Sor/Wiz spell fog cloud [conj] (PH 232) for the purpose of saving a vampire from destruction), that aforementioned wand of quickened no light (without the quickening works, too!), or even—if the DM says it'll make a difference—the martial maneuver iron heart surge. However, if the vampire wants true reliability in avoiding its destruction, it should probably have on hand a very particular potion (see below).
…Then chug potions of cloak of dark power
A potion of cloak of dark power [abjur] (Spell Compendium 48) (1st-level spell at caster level 1) (50 gp; 0.1 lbs.) should be available in all but the smallest town, despite the spell itself being available only as the 1st-level spell of the domain Drow (273). The spell's effect creates around the subject a dusky haze that "does not interfere with vision, but the subject and anything it wears or carries is protected from the effects of full sunlight, even under the open, daytime sky of the surface world." The spell's 1 min./level duration should be sufficient for a vampire to get to safety after the vampire's clothes have been ripped off and its rounds of sunlight endurance nearly exhausted.
If the DM rules the potion isn't available—a strong possibility given the rarity of casters who can trigger the spell so as to create a potion of it—, a vampire can take a full-round action (that somehow doesn't provoke attacks of opportunity) to spread on itself the alchemical substance liquid night (LM 74) (150 gp; 0.5 lbs.). Doing so protects the vampire from sunlight for 1 hour. The cost—both in actions and gp—is higher than for the potion, but a vampire lacking access to the domain Drow may be able to itself manufacture liquid night instead of needing to purchase potions of cloak of dark power from increasingly suspicious vendors. However, both the potion and liquid night have achingly obvious effects—the haze of the potion's effect and the coating of liquid night being a "dark, sticky fluid" that "has a distinct musky odor of moonflower"—, making the presence of either effect a (ahem) dead giveaway that something's not right with the affected creature.