I ended up at one point against twin where we couldn't kill each other. I was playing a variant of soul sisters, and every token they made either wasn't going to offset my life gain, or was going to net me more life. Twin into pestermite, gain 2 life per pestermite token. Twin into Deceiver Exarch, net gain of one life per token. Kiki-Jiki into Restoration Angel, gain one life per token. I couldn't swing in, because I couldn't keep larger creatures on the board. I switched over to Norin and sisters, so I have access to Rending Volley, which works wonders against twin. I might also look into Sudden Shock to fight Kiki-Jiki directly, or any other 1-2 toughness creature in Modern, or even Legacy(except for Geist of Saint Traft and Nimble Mongoose, because I can't target them). Sudden Shock also deals with Mother of Runes, because she can't get Protection from Red in time.