Biggest, Baddest Non Polynorphed Familiar.

[Hesh]

If someone was to go about optimizing their familiar to be the 'big guy' in a big guy is with me, how best to go about it? Preferably a non Improved or Mephit familiar, nor do I want the Druids Animal Companion to be counted as the Familiar, unless its a cute Tiny sized Animal Companion.

The trick is that I don't want it to be polymorphed into some lovely alien creature, but rather that this cute little housecat or owl that can disembowl a Dragon.

Preferably no early entry tricks either please.

[The Viscount]

Is any form changing banned, or is it just polymorph?

Are you using a specific class that grants familiar, or are you gaining one via obtain familiar? This will affect some of what you can do. For example, a hexblade's familiar is inherently tougher than a sorcerer's or wizard's.

As a start you can use a viper or sea snake as your familiar. Then two levels of wyrm wizard, and select venomfire to add to your list. You can buff with true strike as well, and then as long as your target's DR is not interfering, your familiar will be dealing fistfuls of d6's with every bite. You can use greater mighty wallop to improve the bite damage to lessen this problem. If you want to really crank it up, use born energy substitution (electric) and born of three thunders on venomfire for the added option of stunning and tripping enemies. If you're worried about the daze effect you can protect yourself with any least dragonmark and mark of the dauntless, or a third eye clarity.

Its lack of reach means it must enter an opponent's square. You can account for this by taking combat familiar.

[Falontani]

If you are a huge sized creature you can have a LEOPARD
Medium Animal
Hit Dice: 3d8+6 (19 hp)
Initiative: +4
Speed: 40 ft (8 squares), climb 20 ft.
Armor Class: 15 (+4 Dex, +1 natural), touch 14, flat footed 11
Base Attack/Grapple: +2/+5
Attack: Bite +6 melee (1d6+3)
Full Attack: Bite +6 melee (1d6+3) and 2 claws +1 melee (1d3+1)
Space/Reach: 5 ft./5 ft.
Special Attacks: Improved grab, pounce, rake 1d3+1
Special Qualities: Low-light vision, scent
Saves: Fort +5, Ref +7, Will +2
Abilities: Str 16, Dex 19, Con 15, Int 2, Wis 12, Cha 6
Skills: Balance +12, Climb +11, Hide +8*, Jump +11, Listen +6,
Move Silently +8, Spot +6
Feats: Alertness, Weapon Finesse
Environment: Warm forests
Organization: Solitary or pair
Challenge Rating: 2
Advancement: 4–5 HD (Medium)
Level Adjustment: —
These jungle cats are about 4 feet long and weigh about 120 pounds. They usually hunt at night.
The statistics presented here can describe any feline of similar size, such as jaguars, panthers, and mountain lions. Combat
Improved Grab (Ex): To use this ability, a leopard must hit with its bite attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and can rake.
Pounce (Ex): If a leopard charges a foe, it can make a full attack, including two rake attacks.
Rake (Ex): Attack bonus +6 melee, damage 1d3+1.
Skills: Leopards have a +8 racial bonus on Jump checks and a +4 racial bonus on Hide and Move Silently checks. Leopards have a +8 racial bonus on Balance and Climb checks.
A leopard can always choose to take 10 on a Climb check, even if rushed or threatened.
If you are a Duskblade with Obtain familiar your familiar will have full BAB.
Next to improve upon this already awesome familiar, we take 4 levels in the Fleshwarper Class. This gives our familiar +1 size (making it a large familiar) and either a tentacle attack (at d4) or +2? to his natural armor; you could even give him wings.
This does not change what the familiar looks like too much (although wings/scales/tentacle is quite dramatic)
Now depending on your race you could take the Human Heritage feat, ideally you want a tiefiling in your heritage. We'll take The Fiend-Blooded class. One level should be effective enough to grant our familiar the “Fiendish” is an inherited template that can be added to any corporeal aberration, animal, dragon, fey, giant, humanoid, magical beast, monstrous humanoid, ooze, plant, or vermin of nongood alignment (referred to hereafter as the base creature).
A fiendish creature uses all the base creature’s statistics and abilities except as noted here. Do not recalculate the creature’s Hit Dice, base attack bonus, saves, or skill points if its type changes.
Size and Type: Animals or vermin with this template become magical beasts, but otherwise the creature type is unchanged. Size is unchanged. Fiendish creatures encountered on the Material Plane have the extraplanar subtype.
Special Attacks: A fiendish creature retains all the special attacks of the base creature and also gains the following special attack.
Smite Good (Su): Once per day the creature can make a normal melee attack to deal extra damage equal to its HD total (maximum of +20) against a good foe.
Special Qualities: A fiendish creature retains all the special qualities of the base creature and also gains the following.
—Darkvision out to 60 feet.
—Damage reduction (see the table below).
—Resistance to cold and fire (see the table below).
—Spell resistance equal to the creature’s HD + 5 (maximum 25).
If the base creature already has one or more of these special qualities, use the better value. If a fiendish creature gains damage reduction, its natural weapons are treated as magic weapons for the purpose of overcoming damage reduction.
Abilities: Same as the base creature, but Intelligence is at least 3.
Environment: Any evil-aligned plane.
Challenge Rating: HD 3 or less, as base creature; HD 4 to 7, as base creature +1; HD 8 or more, as base creature +2. Alignment: Always evil (any).
Level Adjustment: Same as the base creature +2.
Now remember that for all HD based abilities your familiar uses your Caster Level, so this grants your familiar a much higher SR than normal, and the Smite Good deals much more damage.

Equip gear to your leopard