Because replacement effects are considered before Purphoros is on the battlefield, the mana symbols in its mana cost won't be counted when determining this
If you notice on the bottom right of the card above, theres something that looks like the lore symbols on existing characters cards, only slightly different
This deck is led by face commander, Tidus, Yunas Guardian: a three-mana 3/3 that allows you move counters across your creatures, and to draw a card and proliferate (add additional counters) when your counter-enhanced creature deals combat damage to a player
Though, depending on how late in the match you summon Hades, Namaari might not have the willpower you need
When Sin dies, put its counters on target creature you control, then shuffle this card into its owner's library