I'm interested in a Cane of Kulemak build and I was considering an Impending Doom build.

The problem is you need doom to tick to maximum and afterward, your curse needs to expire.

I was thinking of running the Kulemak Chaos staff with +3 supported and 14% Qual of support gems to get a high level Enhance and Empower on a skill and immediately thought of Impending Doom.

~~The Doom tick rate with this setup would be:

Anomalous Enfeeble(there's also Punishment but that's not as useful) which has 40% doom increased rate at 20%, with Enhance it becomes 142% increased doom rate.

150% doom rate form tree.

20% from Fated End ring.

That increases the doom rate to 312%. That's 41.2 doom rate/sec. As I run Malicious Intent and Fated End and 40 max doom, the hex explodes in [(40-4)/ 41.2]+0.5 second = 1.37 second.~~

Realized stacking Max doom is superior.

Is there a way I could improve this concept?

Find experimental tree. Yes, I know it looks like it's made of paper, this is just a concept. https://pastebin.com/QVX4bFqX

Thanks in advance for your input!