Xanathor, Arcane Master

Instant and Sorcery spells you cast cost
{w}{u}{b}{r}{g} less to cast. For each mana not paid
you lose 2 life. This effect only reduces the
amount of coloured mana you pay.
At the beginning of your upkeep if you both own
and control Xanathor, Arcane Master and an enchantment named The Ritual of Ascension
with three or more Ritual Counters on it,
then you may pay {6}. If you do, you lose 10 life.
Then exile them and meld them into Xanathor
the Ascended.