Though the first will grab you a card or two on occasion, it mostly serves to disincentivize small swings that might have been sent your way on a whim
That would be because of mana burn
Partner (You can have two commanders if both have partner.) Illustrated by Grzegorz Rutkowski Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Legal Comp
The new decks for Archazia's Island definitely feel like they're based on using glimmer team-ups (a trend that's been in Lorcana for a while), which might make customizing the deck a challenge
We haven't gotten a look just yet at the potential rat commander card from this set, but you can take a gander at the Rat King, The Chaosbringer boss card from the set's Turtle Team-Up co-op bundle below
This makes Shadowspear a great tool to slot into equipment packages, Trinket Mages bag of tricks, or simply as a silver bullet to deal with specific metagames