The eye on Danzo's palm is Hikaku's. Its Izanagi lasts for two minutes.
Everyone loved Hikaku. When he died, Tobirama became a ****, Madara and Izuna became dicks and unlocked MS, and Hashirama, became as distraught as the earth itself at the great Uchiha's loss and learnt Sage Mode.
The Seven Swords of the Mist are Hikaku's sparring tools.
Hikaku was the reincarnation...of himself.
Hikaku once fought a Jinchuuriki. He forced it down with just a glare. Not a Sharingan glare...a normal, everyday glare.