Third Male Lead's OOC

The day Wisteria Lilac was summoned by the Sacred Tree to receive his blessing as the Sage Successor, he also recovered his memories of his previous life-- where he had read a novel containing events of his current life and death!
According to the story, he was supposed to be one of the three male leads who fell in love with the protagonist, Fleur Alabaster. However, despite being one of the three male leads, he was fated to fight a heroic battle to his death against the villain!
Having gained the advantage of knowing what will trigger the events towards his death, he becomes determined to avoid such ending at all cost...