Every Saga has three chapters, represented by the I, II, and III symbols. Each chapter also has a corresponding effect. For The Flame of Keld, we see that the effect of chapter I is "Discard your hand." The story gets better, I promise. Some Sagas have the same effect for multiple chapters. Instead of that effect being listed more than once, you'll notice that the chapter symbols are just grouped together with the appropriate effect.

Kicker is an optional additional cost. As you cast a spell with kicker, you choose whether you're just paying the mana cost to get the spell's normal effects. If you have the mana available, you can choose to kick the spell, paying the mana cost and the kicker cost.

Hexproof from black means that Knight of Grace can't be the target of any black spells an opponent controls. It also can't be the target of any abilities of black sources an opponent controls. Spells and abilities that don't target can still affect Knight of Grace.