Muktol

+1
With [[Wild Defiance]] only at 0.86$ average (I nearly choked my lunch seeing this) I would use it 4 times in this deck.
I'm no big fan of [[Epic Confrontation]] and the "fight" mechanic. Domri's Ambush or [[Rabid Bite]] are more to my liking because your creature is safe from your opponents damage. [[Wild Defiance]] lessens this risk but why take it anyway when there are alternatives?
I have used [[Markov Blademaster]] in my vampire deck, but this deck ha a whole ton (nearly 40% of it's cards) of removal and made sure you could actually reach your opponent with the Blademaster. Without proper support it's an expensive 1/1 with double strike that gets killed way to easily. You could replace it with [[Prophetic Flamespeaker]] or [[Storm Fleet Swashbuckler]].

+1
What about adding some imprison-enchantments like [[Baffling End]] (or [[On Thin Ice]] with some snowlands)? this way you can interact with threats your opponent puts on the field.

+1
As this is a rather specialised strategy I would add a description of how to use the colour-change and karma ability to the "how to play" section.
You will run into some problems against multi-coloured deck because they only play as few basic lands as are needed and rely on special lands (like you do) to give them the proper mana when needed. Your only option here is to shut one colour down with [[Swirl the Mists]], so I would up the number of this to 4.

Why [[Tetsuko Umezawa, Fugitive]] and not [[Master of the Pearl Trident]]? if you have Testuko and [[Lord of Atlantis]] on the field this will cancel Tetsuko's effect.

Just stumbled upon [[Claim the Firstborn]]. Should also work fine here.

+1
I would add something that can sacrifice without paying mana. [[Nantuko Husk]], [[Bloodthrone Vampire]] or, if you prefer a slower but enduring strengthening, [[Bloodflow Connoisseur]]. This enables you to play one of your hijack spells and still sacrifice the stolen creature, even if you have no mana left. If you want to gain some life to pump your [[Wall of Flesh]] then [[Disciple of Griselbrand]] could be an option, tough sacrificing with this one costs you {1} mana per creature.
If you're not up for a real aggressive strategy then I would replace [[Hellspark Elemental]] with [[Mogg War Marshal]]. Costs the same but you can sacrifice 3 creatures if you need to.
As for your hijack spells: I would definitely replace [[Act of Treason]] with [[Kari Zev's Expertise]]. [[Harness by Force]] could be replaced with [[Mob Rule]]. [[Wrangle]] only cost's 2 mana, but has some target-restrictions, while [[Traitorous Instinct]] works very good with [[Fling]]. [[Enthralling Victor]] is on the high-side with mana-costs of {3}[R} but he brings a good body that can defend you or attack an opponent and steals a creature.
[[Altar's Reap]] and [[Collateral Damage]] are two good support spells that fit into the deck.

Greetings
Muktol

+1
[[Grateful Apparition]] and [[Hardened Scales]]
[[Servant of the Scale]] can save you a lot of +1/+1 counters when it dies.

+1
[[Colossal Majesty] instead of [[Elemental Bond]] maybe?
[[Autumn's Veil]] could be a way to protect the rest of your spells against counterspells.

+1
What about [[Pride of Conquerors]] instead of [[Borrowed Grace]].
[[Crash Through]] can also come in handy to make sure your creatures pass through your opponent's defence.

A deck and how-to-play description would be a good idea here.

A short deck-description would be a good addition.

+1
What about [[Hero of Bladehold]] instead of [[Entrapment Maneuver]]? Loose a removal, gain a valuable creature (which sadly isn't a soldier itself) and modern legality?
[[Haazda Marshal]] or [[Precinct Captain]] could also be an option instead of [[Champion of the Parish]].

The deck get's updated, tough no one answers. Kind of sad.

+1
Personally I would shift some numbers: -1 [[Brave the Sands]], +1 [[Arcades, the Strategist]], -1 [[High Alert]], -2 [[Leyline of Vitality]] +3 see below

[[Axebane Guardian]]/ [[Overgrown Battlement]]...if you ever feel the need for ramp
[[Order of the Stars]]...defender with colour protection!
[[Bar the Door]]...weaker [[Tower Defense]]
[[Slagwurm Armor]]...defensive equipment

[[Evolving Wilds]] (or [[Grasslands]], [[Misty Rainforest]] and so on) aren't useless at all in single-coloured decks as you remove a land (in addition to [[Evolving Wilds]]) from your cardpool, thus increasing your chances of drawing cards that you want to draw. The only drawback, when using budget searchlands (like [[Evolving Wilds]]) is that it slows you down a little bit.
In this deck in combination with [[Evolution Sage]] you get 2 proliferate triggers when you play and use it's ability. One when [[Evolving Wilds]] enters the battlefield and the second one when the [[Forest]] enters the battlefield. If you have 2 [[Evolution Sage]] you get 4 triggers, and so on.

I would remove [[Forgotten Ancient]]. On one hand it's to slow, on the other hand it's the only card that messes your modern or even pioneer legality.
Also -4 [[Blanchwood Armor]] and -4 [[Forest]] to add 4 [[Evolution Sage]] and 4 [[Evolving Wilds]] (budget choice) or any similar searchland.

Personally I would try to reduce the number of different cards you're using to give the deck some consistency in play. Try to focus on cards that are important for your strategie and use them 4 times.
When using cards like Ajani's Pridemate or [[Bloodthirsty Aerialist]] should rely more on constant lifegain, like [[Soulmender]]'s effect rather than on one-time spells like [[Revitalize]]. Personally I also prefer things I can simply activate (like [[Soulmender]]) over things I have to cast something (like [[Diamond Mare]]) because you can run out of cards or simply don't want to cast a spell every turn.

+1
[[Ballyrush Banneret]] only affects [[Auriok Steelshaper]] and another copy of himself entering so you could look at [[Etched Champion]], [[Kitesail Apprentice]] or [[Auriok Sunchaser]], which are good, aggressive, alternatives. [[Auriok Sunchaser]] having the advantage of not needing to be equipped to be effective and giving you an additional evasive creature.
[[Lightning Greaves]] prevents your opponent from targeting your creatures, but it also prevents you from equipping anything more to this creature. [[Swiftfoot Boots]] would be better here.
Two additional cards that you could take a look at are [[Dispatch]] and [[Infiltration Lens]]

I thought about using something like [[Soulbound Guardians]] or [[Wakestone Gargoyle]] instead of [[Order of the Stars] in that case. Didn't add it to the sideboard until now.

What about [[Intruder Alarm]] (Stronghold version) to make double use of [[Persistent Petitioners]]?