Was trollin around with builds, and I made this for fun

Merc Treads
Manamune
Tri Force
Frozen Heart
Banshees
Blood Thirster/Warmogs/GA (depending on your preference)

And I frikin DOMINATED as mantheon (full metal of course)

Just thought I'd share this build with yall and see what yall think about it. Tons of defense, infinite skill spam (mantheon has mana problems) as well as a good amount of offense from all that mana (and BT if u prefer)

This is how i typically build yorick and skarner, but i noticed this can work for a lot of mana using bruisers that need to spam skills (like mantheon) as you can actually use ur mana for attack dmg rather than choosing between defense, offense, or spammability

Lemme know whatchall think <33

Why Manamune? Panth doesn't really have much mana problems unless you are spamming Heartseeker early (which is bad b/c its damage sucks early). Tossing spears is quite mana friendly and harasses hard.
By mid/endgame, mana isnt much of a problem.

Even with 2k mana pool somehow, MM is still only adding 60AD, and 120 onhit damage to his autoattacks max.
Except Panth DOESNT REALLY AUTOATTACK much. He Spears/Leaps/Heartseekers. Standing there channeling a spear poke isn't really a combo with autoattacking.

He is way better off just getting Bloodthirster(s), Black Cleaver which boost AA dmg, AND all his nice AD ratios.

Muramana applies to single-target spells too. So Spears and Leaps will proc it as well.

That said, it's still bad. Something like Black Cleaver + Last Whisper will do much more for much less than a Muramana + Triforce. ToG and Manamune makes your early and mid game much weaker until the Muramana is completed, which takes quite a while.

Pantheon has really good AD ratios and base physical damage. Wasting that by getting a Muramana is suboptimal.

If you aren't autoattacking after your spear stun heartseek combo, you're doing it wrong