[OP10-090] - Franky (Royal Blood)

During my opponent's turn, my "OP10-090 Franky" was K.O.'d, and I activated its [On K.O.] effect to play "OP04-092 Rebecca" before the activation of this Leader's [Opponent's Turn] effect. In this case, which effect activates first: this Leader's [Opponent's Turn] effect or the [On Play] effect of "OP04-092 Rebecca"?

In this case, this Leader's [Opponent's Turn] effect will always activate before the [On Play] effect of a Character played using the [On K.O.] effect of "OP10-090 Franky".