This should serve as a sign of caution to people intending to play "pure" Summon Reaper.
I realize there are a lot of potential upgrades, especially the jewels, although even "just doubling" the damage should be quite expensive.
Notably, bossing isn't reaper's biggest weakness, it is clear.
The hefty 1s base cast time of Reaper's slash makes it so that it's actually not very effective for clear, specifically for large packs with offscreen potential (e.g. Baran mobs).
Spread out packs, monsters that spawn others and doors are the most punishing to the Reaper's inability to clear.
Last but not least, the reaper is squishy and will occasionally on some maps.
Current PoB: https://pastebin.com/CJsgGJw0