So it's no secret that I absolutely love 4th Edition D&D. I think it's one of the most satisfying systems, mechanically speaking, and opens to door to Role-playing that wasn't obstructed by rules minutia and stats for simply stat-sake. But that being said I still enjoy v3.5 D&D (and 5e too) for other reasons. I have dozens of books for 3e and it would be ultimately silly to remove them, especially when I still have some on-going campaigns using that system.
One thing that I always felt 3e sort of lacked was a "stealthy" style Cleric or divine character. We have divine warriors (Paladins, war-domain Clerics, Favored Souls, and oodles of Prestige Classes like the Ordained Champion) and we have specialty clerics (insert preferred Domain here) and the Cloistered Cleric for that more scholarly aspect. But aside from the Trickery Domain and multiclassing to Rogue, there's really no branch of any church hierarchy for those who fight in it's shadows so to speak. This is sort of the niche that the 4e Avenger filled. So without further ado, here's my conversion of that class to v3.5. As always, constructive criticism is appreciated.
Hit Die: d8
Skill Points: 4 + Int modifier (x4 at 1st level)
Class Skills (and the ability their associated with): Balance* (Dex), Climb* (Str), Concentration (Con), Craft (Int), Heal (Wis), Hide* (Dex), Intimidate (Cha), Jump* (Str), Knowledge (religion) (Int), Listen (Wis), Move Silently* (Dex), Sense Motive (Wis), Spellcraft (Int), Swim* (Str), and Tumble* (Dex). Skills noted with an * are subject to armor check penalties, double for the Swim skill.
Base Attack Bonus: Same as Fighters
Saving Throws: Fortitutude - Poor; Reflex - Good; Willpower - Good
Weapon and Armor Proficiencies: Avengers are proficient with all martial melee weapons and all simple weapons, as well as all light armors.
Spells: You cast divine spells, which are drawn from the Avenger spell list. You can cast any spell you know without preparing it ahead of time. To learn or cast a spell, you must have a Wisdom score equal to at least 10 + the spell level (Wis 10 for 0 level spells, Wis 11 for 1st-level spells, and so forth). The Difficulty Class for a saving throw against your spell is 10 + the spell level + your Wis modifier. You can cast only a certain number of spells of each spell level per day. Your base daily spell allotment is given on Table 1-1. In addition, you receive bonus spells per day if you have a high enough Wisdom score (see Table 1-1: Ability Modifiers and Bonus Spells, page 8 of the Player’s Handbook).
Spells Known: You begin play knowing two 0-level and two 1st-level spells, chosen from the avenger spell list. You also know one additional 0-level spell for each point of Wisdom bonus you have. Each time you gain a new class level, you learn one additional spell of any level you can cast, chosen from the avenger spell list.
Upon reaching 5th level, and at every subsequent odd-numbered level, you can choose to learn a new spell in place of one you already know. In effect, you lose access to the old spell in exchange for gaining a new one. The new spell’s level must be the same as that of the spell being exchanged, and it must be at least one level lower than the highest-level spell you can cast. You can swap only a single spell at any given level and must choose whether or not to swap the spell at the same time that you gain new spells known for the level.
Divine Expression (Sp): You can use the spell-like powers create water, detect magic, guidance, light, and purify food and drink a combined total of times per day equal to 3 + your Wisdom modifier. These spell-like powers do not count against your total of spells known or spells per day.
Faith’s Shield (Su): As the arm of vengeance for your deity, you leave little room for such things as defense, thus your non-proficiency with shields. However, your faith in your purpose to carry out thy deity’s cause gives you an almost shield-like protection. Starting at 1st level, so long as you are not using a shield, you gain a +2 shield bonus to your AC as long as you remain conscious. This bonus only apples to your AC and not to your flat-footed or touch AC. Feats that work in conjunction with shields do not affect this supernatural ability.
At 4th level, this bonus is also applied to your flat-footed AC bonus.
At 7t level, this bonus increases to +4.
Domain Spells: At 2nd level you can choose one domain associated with your chosen patron. This selection adds the domain’s spells to your known spell-list at the appropriate levels listed. At 8th level, you may choose a second domain. You do not gain any additional features, including the domain power when a domain is selected.
Oath of Enmity (Su): At 3rd level, you can choose one enemy within 50-ft. of you that you can see. When you make any attack against that enemy and the target is the only enemy adjacent to you, you make two attack rolls and use either result. This effect lasts until the end of the battle or until the target drops to 0 hit points, at which point you regain the use of this ability. If any other effect lets you roll twice and use the higher result when making an attack roll, this power has no effect on that attack. If an effect forces you to roll twice and use the lower result when making an attack roll, this ability has no effect on that attack either.
At 13th level you may add your Wisdom modifier on any damage rolls
you make while using your Oath of Enmity ability and this feature can be used against one additional target.
Swift Prayer: Beginning at 5th level, you can cast one spell each day as a swift action, so long as the casting time of the spell is 1 standard action or less.
You can use this ability twice per day at 10th level, three times per day at 15th, and four times per day at 20th level.
Spell Power (Ex): Starting at 6th level, you can more easily overcome the spell resistance of any opponent you successfully injure with a melee attack. If you have injured an opponent with a melee attack, you gain a +2 bonus to your caster level check to overcome spell resistance for the remainder of the encounter. This bonus increases to +3 at 11th level, +4 at 16th level, and +5 at 18th level.
0 through 5th level
1st—3/2
2nd—4/3
3rd—5/4
4th—6/5
5th—6/6/2
6th—6/6/3
7th—6/6/4
8th—6/6/5
9th—6/6/6/2
10th—6/6/6/3
11th—6/6/6/4
12th—6/6/6/5
13th—6/6/6/6/2
14th—6/6/6/6/3
15th—6/6/6/6/4
16th—6/6/6/6/5/2
17th—6/6/6/6/6/3
18th—6/6/6/6/6/4
19th—6/6/6/6/6/5
20th—6/6/6/6/6/6
0: caltrops, disrupt undead, inflict minor wounds, message, resistance, virtue
1st level: armor lock, bane, benign transposition, blade of blood, bless, command, divine favor, doom, guiding light, inflict light wounds, lesser vigor, light of Lunia, magic weapon, rhino’s rush, swift expeditious retreat, updraft.
2nd level: baleful transposition, bull’s strength, darkness, darkway, deific vengeance, dimension hop, distracting ray, earthbind, glitterdust, hold person, inflict moderate wounds, levitate, light of Mercuria, see invisibility, seeking ray, sting ray, sun bolt, owl’s wisdom, remove paralysis, silence, spiritual weapon, swift fly, zone of truth.
3rd level: bestow curse, darkfire, daylight, footsteps of the divine, inflict serious wounds, invisibility purge, knight’s move, light of Venya, prayer, protection from energy, ring of blades, searing light, vigor
4th level: air walk, castigate, dimension door, dispel magic, dimensional anchor, discern lies, inflict critical wounds, Otiluke’s resilient sphere, radiant shield, shadow well, sound lance, spell immunity, wingbind
5th level: break enchantment, dualward, flame strike, greater command, prismatic ray, righteous wrath of the faithful, slay living, spell resistance, swift ethernalness, true seeing
When you make any attack against that enemy and the target is the only enemy adjacent to you, you make two attack rolls and use either result.
I should note that this only affects one attack (per turn, though your choice depending on how many attacks you get), so when you're using the Full-Attack Action you're not going to get to roll double the amount of the full set. It does, however, allow you to use this feature on Attacks of Opportunity.