Build Advice For Two Characters

I am looking for advice on two characters i have been working on for a little bit now.
I am not new to the game however i have not put in a ton of time to learn everything so all the help would be great.

First character- OdinNova - Shadow COC.
/This character i can do a lot of higher maps however once i get into tier 13-16 i can eaily get one shot, so i am looking to see if i can do anything to prevent that or how to make my build better.
As a side thought i have been using this character for much linger than 3.9 and never had an issue with sustaining mana until a few days ago, now all of the sudden i am unable to sustain mana during cyclone for awhile.


Second Character- ODIN_NECRO - WItch Necro.
/I did just start building this character and it has been going pretty well during the leveling, now the story is done and i started mapping.
I started this character to get into endgame as my Nova was a little too squishy for endgame. I would like to be able to take this character into the high tier maps and clear them well, at the current time i can run a 1-4 but it tends to slow down a lot on the boss at tier 4 and a few Zombies can die still.
The weapon i am using on this character is not showing on my profile as i am currently linking it but i run Queens Escape with raise zombie, feeding frenzy, maim, multistrike, mellee phy damage, and empower once i get the 6link.

any help on both of these builds would be great!

https://www.pathofexile.com/account/view-profile/KILLAODIN/characters