While you control Festival of Embers, abilities that trigger whenever a creature you own dies won’t trigger because those cards and tokens are never put into your graveyard.

When Festival of Embers’s last ability resolves, it will be exiled.

If Festival of Embers is destroyed by a spell, Festivals of Embers will be exiled and then the spell will be put into its owner’s graveyard.

If you discard a card while you control Festival of Embers, abilities that function when that card is discarded (such as madness) still work even though that card never reaches a graveyard. In addition, spells or abilities that check the characteristics of a discarded card can find that card in exile.