Ivandis flail

The Flail of Ivandis is created by the player during the Legacy of Seergaze quest using a Silvthril chain, Silver sickle(b), the Rod of Ivandis and an emerald.

It is the only method available to kill the Vyrewatch, as it contains Silvthril enchanted by mortal means (enchanted sapphire) and divine means (dipped in the well connected to the River Salve, which harms vampyres. But the Rod of Ivandis itself won't do on the Vyrewatch, because they have a minimal mind-reading ability which lets them predict and avoid damage. The Flail of Ivandis counteracts this by being incredibly unpredictable, because it is a hard weapon to master (even if the vyrewatch know how you intend to hit them, you won't hit them the way you intended, rendering their mind-reading useless) and the shape of the silver sickle for the head increases the unpredictability of the weapon.

It can be used as a Silver sickle(b), and used in place of a Rod of Ivandis, with 30 starting charges. This lets a player kill Ghasts, Vampyre juvinates, and Vyrewatch with a single weapon. It can also autocast all of the basic elemental combat spells.

On the official Runescape forums, a Jagex Moderator pointed out that continuous use of the flail on the Vyrewatch will "improve" your ability with it. Players report getting a message in game(after 75-100 Vyrewatch kills and cremations) stating that they feel like they have improved with flails. This did not however change the stats when equipped. Nothing more is known about this at this time.