Leveling PoB for lvls 1-90, including skill gems and passive tree per act: https://pobb.in/GXvapcjEM51C
tl;dr
- Run with rolling magma until the end of act 4.
- Before Malachai fight switch to storm brand with arc.
- Enjoy your big cock damage with decent clear.
Concept:
The build is using arc as supplementary skill for storm brand.
Arc + Unleash + Overcharge offers 1-tapping clear and a very strong shock to enhance the damage of the storm brand.
Using this pair negates the weak points of two skills - the storm brand offers a good single target damage, and the arc offers a good clear.
Also, we are using the hydrosphere to apply -18% Lightning Exposure with Elemental Mastery.
The uptime of the Elemental Overload is very good for both skills.
I'm also quite fond of MoM during acts, pool is enough for taking some big hits.
By the lvl 90 with a pair of Singularity sceptres (1-2c each day 1), the Mark of Submission (1-5c day 1), and a random 6-link, the build nets about 4m pinnacle dps with lvl 19 gems.
I'm fine playing glasscannons, so feel free to add some defense by yourself.
Also, there is the guide for the build with some endgame videos: https://www.pathofexile.com/forum/view-thread/3390881
Enjoy.
