I will only comment on the slotting as the power choice is pretty good 
3 recharge in siphon speed.
Increase density, 3 damage res seems overkill one is largely enough.
Inferno needs 3 damage
Fulcrum shift, well i don't find the range SO usefull at all, because you will be in the middle of it anyway and i don't think range SO do increase the radius of fulcrum shift. So, 2 acc 3 recharge.
I highly recommend picking up Hasten. Once you have SO, you can stack up to 3 siphon speed and hasten is nearly perma with a 30 sec, give or take, down time.
Not too experienced with the Fire set, but i would ditch fire breath for hasten.
If I was only ever going to team with said stone tank, here is how I would do it. If you ever team with others, take increase density instead of inertial reduction. If you ever want to PvP, dump fire breath and jiggle things about (and by that I mean powers 
)
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Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder - (http://sherksilver.coldfront.net/index.php)
---------------------------------------------
Name:
Level: 41
Archetype: Corruptor
Primary: Fire Blast
Secondary: Kinetics
---------------------------------------------
01) --> Fire Blast==> Acc(1) Acc(31) Dmg(34) Dmg(37) Dmg(40)
01) --> Transfusion==> Acc(1) Acc(3) Heal(3) Heal(5) Heal(5)
02) --> Siphon Power==> Acc(2) Acc(31)
04) --> Fire Ball==> Acc(4) Acc(7) Dmg(7) Dmg(9) Dmg(9)
06) --> Swift==> Run(6)
08) --> Fire Breath==> Acc(8) Acc(11) Dmg(11) Dmg(13) Dmg(13)
10) --> Siphon Speed==> Acc(10) Acc(15) Acc(15) Rechg(17) Rechg(17) Rechg(19)
12) --> Combat Jumping==> Jump(12)
14) --> Super Jump==> Jump(14)
16) --> Hurdle==> Jump(16)
18) --> Blaze==> Acc(18) Acc(19) Dmg(21) Dmg(21) Dmg(23) Rechg(40)
20) --> Speed Boost==> EndMod(20) EndMod(23) EndMod(25)
22) --> Stamina==> EndMod(22) EndMod(25) EndMod(27)
24) --> Acrobatics==> EndRdx(24)
26) --> Aim==> Rechg(26) Rechg(27) Rechg(31)
28) --> Hasten==> Rechg(28) Rechg(29) Rechg(29)
30) --> Inertial Reduction==> EndRdx(30)
32) --> Inferno==> Dmg(32) Dmg(33) Dmg(33) Rechg(33) Rechg(34) Rechg(34)
35) --> Transference==> Acc(35) Acc(36) EndMod(36) EndMod(36) EndMod(37) Rechg(37)
38) --> Fulcrum Shift==> Acc(38) Acc(39) Rechg(39) Rechg(39) Rechg(40)
---------------------------------------------
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Scourge==> Empty(1)
02) --> Rest==> Empty(2)
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IN MEMORIUM OF GAYBABY
CRUELY TAKEN FROM THIS WORLD WHILE SO YOUNG
You dont need acc in inferno as it had an inherant bonus and should be used after aim. Preferably Aim>Fulcrum>Inferno (awaken for when it all goes wrong )
I'd drop ID for hasten and slot inferno for 3 recharge 3 damage, making for some impressive nukage very regularly. As you plan to duo with a granite brute he will require niether the status protection nor the resistance from ID. More end mod in speed boost may benefit him far more.
I miss him in the weeping of the rain;
I want him at the shrinking of the tide;
The old snows melt from every mountain-side,
And last year's leaves are smoke in every lane;
But last year's bitter loving must remain
~Edna St. Vincent Millay
speakin from the brute's side (stone/stone here, teamed with a fire/kin corr), deffo put more endmods in speedboost! stone/stone as i found out is pretty heavy on the blue stuff, so every bit of extra recovery is appreciated. My partner has it 3slotted with endmods and I still manage to run low on end if im not careful and run both rooted and mudpots + armors. Also as said before, if you always team with said brute, ditch ID as rooted/granite offers more than enough mez resist. Take hasten instead, especially for when you get transference/fulcrum.
"god, how many devs did hami have to sleep with to get ED?"
Total Cat @Stagefright
Just gonna pipe up cause I'm the granite brute.
Basically she's going to be Super Strength/Stone Armor. Built to be the ultimate Brute tank in granite. Permarage/hasten/rech redux should fix my problems with -dam and -rech from granite for the most part. Also taking Aid Self, Tough and Weave for maximum defense/resists.
Hmm. Not sure what to add really. o_o But might help to know my rough build, for people making comments.
Some ideas besides the ones already expressed, I agree Hasten is definitely worth it, Inferno doesn't need Acc and Nefarious manages to run low on endurance even with 3-slotted Speed Boost. You can add them if needed and respec them out after you get Transference, though. 
Keep Fire Breath but put a Range enhancement into it. Without the range it's a bit meh but with it it's suddenly awesome. I think you could get it in the 20s, though, and get Stamina two levels earlier. By that time you'll be really hurting for endurance. Some damage slots in Fire Blast could also be worth it. Personally I didn't take Blazing Bolt, it's a good snipe but I don't feel snipes really fit /Kinetics. The 4 attacks I have are plenty enough because my recharge rate is so good with Hasten and stacked Siphon Speed, and Kinetics can keep you really busy.
I don't have ID yet but might pick it up in the 40s, the brute won't need it but it's nice to have if you team a lot with other squishies. If you get Hasten you can also drop some recharges from the secondary. I have 3 accs in Transfusion and I'm always glad of it when fighting CoT.
Question from me now because I'm just wondering.
Enhanced Stamina adds +1 end per second, and takes 3 power slots to get it. Is this really needed on a /kin with Transference? If it transfers 60 end per use, and it recharges every 15 seconds, doesn't that add up to +4 end per second, while only taking 1 power instead of 3, and being 4 times as effective?
It isn't really needed, however a /kin only gets transference at 35, while stamina is available at 20.
Yeah, I've played one of these to level 10, and was already really hurting for endurance, I intend to get stamina at 20, then do a respec at 35.
I really should do something about this signature.
I think I will keep Stamina for my fire/kin even now that I have Transference. Before Transference I was constantly out of endurance, even with 3-slotted Stamina. It goes through endurance at an amazing rate. I'm also not sure I'd want to spam Transference every 15 seconds, the set is just too busy for that.
[ QUOTE ]
I'm also not sure I'd want to spam Transference every 15 seconds, the set is just too busy for that.
[/ QUOTE ]
Well, now that end drain is useful again, I find myself spamming transference for that (rather than the endurance gain) all the time ...
Synaesthetix:if your mum wasn't already dead I would go kill her for bringing
you into the world
---------------------------------------------
Exported from Ver: 1.7.6.0 of the CoH_CoV Character Builder
---------------------------------------------
Name:
Level: 41
Archetype: Corruptor
Primary: Fire Blast
Secondary: Kinetics
---------------------------------------------
01) --> Fire Blast==> Acc(1)Acc(17)
01) --> Transfusion==> Acc(1)Acc(3)Heal(3)Heal(5)Heal(5)Rechg(9)
02) --> Fire Ball==> Acc(2)Acc(7)Dmg(27)Dmg(27)Dmg(37)
04) --> Siphon Power==> Acc(4)Acc(7)Rechg(9)Rechg(40)
06) --> Combat Jumping==> EndRdx(6)
08) --> Fire Breath==> Acc(8)Acc(11)Dmg(17)Dmg(23)Dmg(23)
10) --> Siphon Speed==> Acc(10)Acc(11)Rechg(15)Rechg(15)
12) --> Aim==> Rechg(12)Rechg(13)Rechg(13)
14) --> Super Jump==> Jump(14)
16) --> Hurdle==> Jump(16)
18) --> Blaze==> Acc(18)Acc(19)Dmg(19)Dmg(21)Dmg(21)
20) --> Speed Boost==> EndMod(20)
22) --> Swift==> Run(22)
24) --> Stamina==> EndMod(24)EndMod(25)EndMod(25)
26) --> Acrobatics==> EndRdx(26)
28) --> Blazing Bolt==> Acc(28)Acc(29)Dmg(29)Dmg(31)Dmg(34)
30) --> Increase Density==> DmgRes(30)DmgRes(31)DmgRes(31)
32) --> Inferno==> Acc(32)Acc(33)Dmg(33)Dmg(33)Rechg(34)Rechg(34)
35) --> Transference==> Acc(35)Acc(36)EndMod(36)EndMod(36)Rechg(37)Rechg(37)
38) --> Fulcrum Shift==> Acc(38)Acc(39)Range(39)Range(39)Rechg(40)Rechg(40)
---------------------------------------------
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Scourge==> Empty(1)
02) --> Rest==> Empty(2)
---------------------------------------------
Just wondering if it handles decently; first time I've made a Corrupter, heh.
Mostly worried about attack slotting; I want to do damage, but not sure if I've left the attacks too late.