23 Jun 2020
While resolving Kels's middle ability, you can't pay {U/B} more than once to draw more than one card.
23 Jun 2020
Kels's middle ability is a triggered ability, not an activated ability. It doesn't allow you to sacrifice a permanent whenever you want; rather, you need some other way of sacrificing permanents, such as Kels's last ability.
23 Jun 2020
If you sacrifice Kels, its middle ability triggers. It also triggers for any other creatures you sacrifice at the same time. You can sacrifice Kels to pay the cost of its own ability.
23 Jun 2020
You can activate Kels's last ability even if nothing's about to destroy it and even if it already has indestructible.
23 Jun 2020
A legendary permanent that is put into a graveyard because of the "legend rule" isn't sacrificed.
23 Jun 2020
If you sacrifice a permanent as part of a spell or activated ability's cost, Kels's middle ability will resolve before that spell or ability.