Kentaro, the Smiling Cat

[Upinthe]

If I play Metamorphosis or a similar card, can I use mana from that with Kentaro's ability?

[Limbo]

Metamorphosis:
As an additional cost to play Metamorphosis, sacrifice a creature.
Add X mana of any one color to your mana pool, where X is one plus the sacrificed creature’s converted mana cost. Spend this mana only to play creature spells.

Kentaro, the Smiling Cat
You may pay X Mana rather than pay the mana cost for Samurai spells you play, where X is that spell’s converted mana cost.

As you still play the spell, Methamorphosis mana should do the trick nicely.