The IAU is mostly just a basic spiker, but is also required to pull groups of enemies at Black Beast and 6-0, as well as killing a pair of tendrils, like the TK. Although the role is not too complicated, certain parts of the job are considered more challenging, so players are usually discouraged from learning IAU until they are at least familiar with TK.
The IAU's counterpart in 3-3 tactics is the Empathy spiker.
- Heart of Shadow is usually on the bar to help with pulling 6-0 and Black Beast, and for general mobility.
- YMLaD is often taken, to interrupt the Black Beast and for general use.
- Shatter Delusions is sometimes taken, for additional AoE damage shattering VoR on large balls.
- Recall is sometimes taken in place of Heart of Shadow if the team starts in Gloom since the IAU will not need to pull groups at 6-0. IAU is also usually dropped, for an extra spike skill.
For general spikes, the IAU simply damages the main ball, using YMLaD to clean up leftovers. DoA Spiking Guide
In French tactics, simply follow the main team to ranger lord and kill it.
In other tactics, go to the derv lord hill after 360. The TT runs in, grabbing aggro, and pulls the mobs back towards 360. The lord will break on its own. You run in, ideally without aggroing any of the other mobs (Use YMLAD in case of additional aggro). Pull the lord with a long/flatbow, or by using a skill if you can get close enough without taking more aggro. Run back to the MLK and use your skills to kill the lord. After the lord is dead, wait until the tank has pulled the mobs away, and run past, back to 360.
Go down the trench, where the team should already be turtling the trench pops. After spiking clover pull and the group towards ele lord, the IAU and VoR backtrack to necro lord. Wait until the lord is clear of other aggro, and then use all your damage except YMLaD to kill it, especially Mistrust. Save YMLaD for finishing the Lord.
Stand in position in between your 2 tendrils. Make sure you have Prot Bond; you may also get Life Bond, but this is not required. Pop your summon, and cast Arcane Echo. If AEcho runs out, cast it again. When the quest is taken, cast PI on both of your tendrils, and deal some extra damage to each tendril. Kill the back one first if you can. Use IAU, make sure you have aggro of both the groups that spawned, and run back to the team, using HoS if you get stuck or need a heal.
In French tactics, go with the emo to the rift. Kill the right torment claw and cap the rift, before running to Deathbringer.
In other tactics, stay with the other spikers at cave. After the spike, let the TK Recall you and run towards the start of Gloom. This video shows the VoR doing the Recall chain, but in modern tactics it's the IAU's job.
In Golt tactics, IAU is responsible for focusing on Dream Riders, shutting them down with Mistrust and YMLaD.
Once the team arrives at the Black Beast gate, and is clear of aggro, make sure you're bonded and have plenty of health, and then run in to spawn the Black Beast. It's not necessary to go deeper to aggro the Beast - as soon as it's spawned, it will come out towards you. Right wall block the titans, target the beast, and interrupt its Touch of Aaaaarrrrrrggghhh with YMLaD. Finish off all the titan spawns, and then go to spike the Fury.