ShadowSpace

I have a Bots/ Time Manipultaion build and I am getting close to the level 35 where I get to pick an Ancillary Power Pool. It looks like the choices are
Chill Mastery
Charge Mastery
Heat Mastery
Field Mastery.

I use my Time Manipulation on the enemy and kill with My bots.
I don't do to much of my own damage, just time manipulate to slow down enemy and blast away with Bots
I am wondering which will work best with this strategy. I would appreciate all suggestions. Do not want to spend time to get the access to the Villan power pool with End of the World looming.
I and bots have very little Defense and Resistance, would Chill Mastery help protect the bots?

thanks for the help.
I went with a Bots/Time and at lvl 33 and very happy with it.

I have only been playing the game for about 3 months now. I have only 1 50+ incarnate level toon. A Science Scrapper, DM/Regen can take a lot of damage and deal a lot of damage. I love this build and feel I got lucky and picked one of the best builds for me on my first try.
I would like to build another toon through to 50+, but not sure what to build.
I love my Scrapper DM/Regen and I like to solo a lot.
I have a Blaster Ice/Energy build to about lvl 23 and a Brute WarMace/ElectricArmor to lvl 23 also. I am not to happy with these builds. The Blaster is nice with the Ice to slow down and damage, but seems like running most time and blasting only when get a chance. I think the Brute might just be starting to be fun to be able to stay alive long enough for me to start doing damage.

I am asking what suggestions do you have for a build I should try as my last 50 attempt, before the COH world ends?
Or should I stay with my Blaster Ice/Energy?
Or should I stay with my Brute WM/ElectricA
I love my Scrapper DM/Regen. I like to solo, but know ultimately this is a team game. I would like to know what suggestions you all have as the build I should try to be my 2nd and last 50+ toon.
Looking for Archetype, Primary and Secondary Powers suggestions
Will answer more questions as needed to help with suggestions.

In advance thanks for all the help.

Thanks for the advice.
I went with Blaze Mastery.
Did not want to go through change from Hero to get the Soul Mastery.

I have a Dark/Regen Scrapper and I would like some Help with Epic Pools.
Blaze Mastery?
Body Mastery
Darkness Mastery
Weapon Mastery
Of the 4 pools none of them seem real good
I am leaning towards the Body Mastery For the Focused Accuracy and then Physical Perfection to make my Scrapper even tougher.
Though Dark Mastery looks like it might add to my Dark primary while allowing to hold foes.
----Getting tired of having to chase foe arround, because of best powers are close up.
None of the pools seems to give to much ability to damage for Ranged.

Playing style is that I like to run up and attack a foe or group of foes and start pounding away. If health drops to low, just back off hope pull just a few while health regens.
Am I missing something?
Any suggestion on which Pool to take?