https://wiki.project1999.com/Nevederia%27s_Horn
Strong aggro proc. Delay is 15. Offhand does not apply actual damage bonus damage but there is a bug on p99 where offhand DOES contribute damage bonus threat. It is a bug, but it exists and that weapon applies that damage bonus threat at a delay of 15.
It is the best offhand aggro weapon currently in game. Red epic with its proc edges out over all other mainhand threat weapons available in this era.
Best of the best for raw aggro is red + nev
Having said that, as long as you’re making more than enough threat to reliably get the job done, there is value in other weapons (utility from slow proc, more hp, etc).