Summon: Magus Sisters

Randomness is the trap most Saga designers steer around, and this one walks straight into it: three chapters, each firing one of three effects chosen at random, so across the card's life you cannot know whether you are getting a pile of +1/+1 counters, a shield-plus-lifegain package, or a fight trigger. What makes that gamble tolerable is the body it is stapled to. A 5/5 with haste can swing the turn it lands, but Sagas trigger Chapter I the moment they enter, so the first random pick resolves in your main phase before combat, with the attack arriving afterward. That sequencing matters: the enter-and-attack rate gives you a floor no matter which face turns up, and the Saga text sits on top as upside rather than a plan. The three outcomes are also unusually non-overlapping in what they want. The counter mode rewards a target worth pumping; the shield mode is defensive and self-serving, buying a life buffer and a damage-eating counter; the fight mode turns the Saga's own oversized body into removal against an opponent's creature. Nothing about fighting requires haste, incidentally: any creature can fight the turn it enters, since fighting neither taps nor attacks. You are not building around any one mode; you are building around the fact that a hasty 5/5 pays for itself regardless of the rolls. It is a design that accepts variance as flavor instead of fighting it, and leans on the body to keep the random results feeling like bonuses.