The form of Vishnu, among the Trimuti, is a manifestation of pure Sattva. Brahmaa is the manifestation of abundance of Rajas with a trace of Sattva. Whereas, Thy form known as Shankara has an abundance of Sattva but Tamas expresses itself in its activities.
Thou do transcend the Trinity and are the Supreme Being. Thou are the essence of all and Shaivas worship Thee alone as Shiva with worshipping norms, as described. That too is Thy form alone. We have many proofs in support of this truth.