Hi, I came up with a pretty good build for an esoteric Magus, though it only comes online at level 10.

The essence of this build is Martial Versatility, so you have to be some kind of human and you can only pick it up once you get to level 10 (because of fighter training).

Feats required are: Weapon Focus Unarmed Strike, Martial Versatility, Ascetic Style and Ascetic Form.

Martial Versatility:
Benefit: Choose one combat feat you know that applies to a specific weapon (e.g., Weapon Focus). You can use that feat with any weapon within the same weapon group.

Ascetic Style:
Benefit(s): Choose one weapon from the monk fighter weapon group. While using this style and wielding the chosen weapon, you can apply the effects of feats that have Improved Unarmed Strike as a prerequisite, as well as effects that augment an unarmed strike, as if attacks with the weapon were unarmed attacks.

Ascetic Form
Benefit(s): You can use the chosen melee weapon with any class ability that can be used with an unarmed strike, such as an unchained monk’s style strike ability. In addition, you are treated as a monk with a level equal to your character level for the purpose of determining the number of times per day that you can use feats with uses per day that depend upon your monk level, such as the Stunning Fist or Perfect Strike feats.

By having these 3 Feats, you can apply your Arcane Pool to all of your natural attacks (with a single use), particularly nice, impact.
You can also apply the monk damage progression to all your natural attacks. At level 10, turning into a 4 Armed Gargoyle, that's 6 primary attacks with 10 feet that all deal 2d8. But turning them into impact weapons treats them as a size higher, so they would be at 3d8. Now if you had a wand of Strong Jaw your claws could count as 2 size categories bigger, which would make them colossal at 6d8. At level 20 that could be as high as 12d8.
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The weapon sizes comes from different sources. One is because you're a larger. One is a weapon enchantment. One is a spell.

More good news, since you can apply all feat or class feature dependent improvements to your natural attacks, you can deliver touch spells with any of them. I'm sure there are some ki dependent feats you could throw into the mix but I don't know too much about it.

The muscle magus casts fist.