With Neera in play, you can choose to put the spell youre casting on the bottom of your library, and flip cards off of the top until you get a nonland card, which you can then cast for free
You can read my article about forever decks if you want some inspiration for what that might entail
Its main ability lets you play cards from the top of your library, while its second provides card selection in the form of surveil
Note that these are the cheapest printings with full text available
Any player other than the battles protector may have creatures attack that battle in combat, and the protector can assign blockers for that battle
What makes this even stronger is that it has a flashback cost of 3 mana, so you can cast it from your graveyard before you exile it, meaning you can get 2 uses out of this great card