7 year 10 mo super-lurker here, (54 posts, most of which was within the last month or so) ready to follow whatever incarnation MTGSalvation becomes! I love the spoiler layout of MTGSalvation and its community discussions, even though I rarely took part in the discussions myself.
Thank you to the creators/owners/mods/community for making MTGSalvation an enjoyable spoiler/idea hub for us lurkers!
On the story/lore, I was expecting Gideon to become one of the Ravnica spirits, just like how Elspeth became a resident of the Therosian underworld. Perhaps someone planeswalked with him as he was dying to Theros? Maybe the Therosian gods call their true heroes home, like Disney's Hercules?
As for the card itself, I can't imagine how this would be useful in standard, except for possibly flushing a hand that's land-swamped or that's been revealed to an opponent? Not very many white/red graveyard strategies I think.
It paints such a metal picture of Gideon in this fight that I'm into him. Wait, wait....
Obviously the Giant is a plant for commander Najeela with its Warrior typing.
Kidding aside, these look like limited or Brawl options. If power 4 or greater is a thing in limited, the Rogue might be a way to slip around that. Otherwise these cards don't seem to have too much application elsewhere.
I looked up on Gatherer for other examples of "defending player", and it appears that "defending player" refers to each specific defending player and the creature attacking said player. Especially with Storm the Citadel, because the creature gains that ability; the player that creature is attacking becomes that creature's defending player.
So my creatures A, B, and C under a resolved Storm the Citadel attack their respective players A, B, and C. Player C blocks all damage, and Players A and B are hit by their respective creatures. I get a trigger from creature A to destroy one artifact/enchantment player A controls, and another trigger from creature B to destroy one artifact/enchantment player B controls. Nothing further happens to player C.
As long as you have a couple PWs out, this outgrow most burn spells in standard.
Barring shenanigans, Green and Black have a one-time use ability on ETB, meaning you'll pull it off once every 3 turns in a vanilla game? Red is upon attack, so once per turn barring extra combat steps. Blue counts the first card you draw each turn, so instant speed card draw enables near "once on each player's turn" but it has a pretty high mana requirement.
Oketra on the other hand comes down when you have a lot of mana for white and then you can get multiple value per turn if you're able to play only creatures. Cards able to abuse Oketra include the aforementioned Whitemane Lion, Kor Skyfisher, Emancipation Angel, Stonecloaker, or in other colors, Shrieking Drake, Dream Stalker, Fleetfoot Panther, Silver Drake, Sawtooth Loon.
The card itself is decent enough; 2B for 2/3 with an upside of cashing in a worn out uncommon walker or a creature/walker that's about to die to combat/spell. Like your Tibalt who's made 2 tokens against a non-life gaining deck.
I kinda wish the ability cost was 2 instead of 3 for easier accessibility, but it's probably common-rarity balanced better this way.
Edit: Also super secret anti-Elderspell tech, right here.
+1: Destroy a card in hand or on the battlefield.
-3: Destroy a creature or planeswalker.
-8: Destroy one (or more) opponents.
In standard, can grief-more with Nicol Bolas, the Ravager turn 4, Nicol Bolas, Dragon-God turn 5, flip Ravager to be Nicol Bolas, the Arisen turn 7. Or earlier with ramp. Could make for a brutal mid-range Grixis deck?
Edit: I'd like to see a deck that runs a bunch of planeswalkers so they can Elderspell their own PWs and ult one of their remaining PWs. If the opponent plays any of their own PWs then they'll just become lunch for your ult target as an added bonus.
Turn 2 Submarine into turn 3 Tempest Djinn could be a thing.