Its very similar to Sapphire Drake
And, yeah, judging by the Wilds of Eldraine printing, which was also part of a bonus sheet ( Enchanting Tales ), these are actually the expected prices even well after the set's hype dies down
All permanents you control phase out. Being phased out means that nobody can interact with your permanents in any way
Krrik essentially only costs 4 Mana to cast, by paying 6 life to get Phyrexian Mana
It's unclear whether this was the most necessary of the Slivers, but it was the one that frustrated the most opposing plans to deal with the problem and even opened up new game plans when the card advantage resulting from saving your creatures could allow Sliver decks to go the control route when backed up by counters and removal spells
As a dedicated "Summon"-centric legend, Yuna seems like fertile ground for open potential in deckbuilding