solo - use ROTPO and Drop Iceheart shoulders for Diamond shoulders

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Explanation: The core of Necromancer rotations looks like this:

Stalking Blastbones > Spammable > Spammable > Stalking Blastbones > Spammable >Spammable
-repeat-

For this build, the spammable is Ricochet Skull

Stalking Blastbones is your highest DPS ability, therefore the idea here is that you are casting it every time its off cooldown, which means you are casting it every third ability.
ESO Skills Stalking Blastbones

*You will replace the spammable (Ricochet Skull), with whichever dot is falling off at the time, but you will always cast Stalking Blastbones every third ability. If all dots are up, you cast Ricochet Skull between Stalking Blastbones. Enjoy!