transform.rotation - 90 unity

//This way you can add a specific of degree (in this case 90 on y) 
//to a specific axis
rotation *= Quaternion.Euler(0, 90, 0);

 var lookPos = target.position - transform.position; lookPos.y = 0; var rotation = Quaternion.LookRotation(lookPos); rotation *= Quaternion.Euler(0, 90, 0); // this adds a 90 degrees Y rotation var adjustRotation = transform.rotation.y + rotationAdjust; //<- this is wrong! transform.rotation = Quaternion.Slerp(transform.rotation, rotation, Time.deltaTime * damping);