With a kin all the way then i dont see a point in taking most of it. 
Its a good build, and its easy to alter whats in a slot for soloing because the slots are there.
He will honor his words; he will definitely carry out his actions. What he promises he will fulfill. He does not care about his bodily self, putting his life and death aside to come forward for another's troubled besiegement. He does not boast about his ability, or shamelessly extol his own virtues. - Sima Qian.
Yep, as Shannon says - the slots are there. With a kin the +recharge and +end gives you some options. On my Spines/Dark I have End redux instead of recharge in attacks and one in all shields.
Something to consider.
As you obtain toggles etc, you'll notice which ones will need attention and can make alterations as required.
With that build u will possibly have end issues even with sb, but worth giving it a try tho
Indeed looks very end heavy,i slotted my end heavy attacks with 2 end red and others 1 end red, also put one Dark Embrace,Murky Cloud,Obsidian Shield,
so even with a kin you may have probs especially when your having to heal alot DR good power but sucks your end quiet badly i had to build mine v different then you didnt have the luxury of a kin by my side all the time.
only thing i would change is maybe acrobatics for knockback protection i think kins ID has knockback protection but as far as im aware the effect doesnt last long, so might be worthwhile i hate knockback so its a must for me.
oppresive gloom im not sure putting 2 end red is needed i think its very low on end cost [i could be wrong but its doesnt seem very end heavy to me].
im not sure about 3 slotting health didnt think it was that useful to be honest could be wrong with spines/dark im sure those 2 slots would be better suited elsewhere.
I see no CoD i didnt fit it in right away but i find it useful but thats me 
Anyways taking that your gonna have a kin with you at all times maybe your end will be fine well after Sb has been 3 slotted end mod as your gonna need as much help as poss.
Hope some of that helped could be wong in some area's but im sure someone will correct me if i am, enjoy anyways very fun build i found, without a kin challenging but all in all great fun.
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Name:
Level: 50
Archetype: Scrapper
Primary: Spines
Secondary: Dark Armor
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01) --> Lunge==> Dmg(1) Dmg(3) Dmg(3) Acc(5) Acc(5)
01) --> Dark Embrace==> DmgRes(1) DmgRes(7) DmgRes(7)
02) --> Spine Burst==> Dmg(2) Dmg(9) Dmg(9) Rechg(11) Acc(11) Acc(13)
04) --> Death Shroud==> Dmg(4) Dmg(13) Dmg(15) Acc(15) Acc(17) EndRdx(17)
06) --> Hurdle==> Empty(6)
08) --> Combat Jumping==> Empty(8)
10) --> Impale==> Dmg(10) Dmg(19) Dmg(19) Acc(21) Acc(21) Rechg(23)
12) --> Murky Cloud==> DmgRes(12) DmgRes(23) DmgRes(25)
14) --> Super Jump==> Empty(14)
16) --> Health==> Heal(16) Heal(25) Heal(27)
18) --> Quills==> Dmg(18) Dmg(27) Dmg(29) Acc(29) Acc(31) EndRdx(31)
20) --> Stamina==> EndMod(20) EndMod(31) EndMod(33)
22) --> Obsidian Shield==> DmgRes(22) DmgRes(33) DmgRes(33)
24) --> Dark Regeneration==> Heal(24) Heal(34) Rechg(34) Rechg(34) Acc(36) Acc(36)
26) --> Ripper==> Dmg(26) Dmg(36) Dmg(37) Acc(37) Acc(37) Rechg(39)
28) --> Hasten==> Rechg(28) Rechg(39) Rechg(39)
30) --> Cloak Of Fear==> Fear(30) Acc(40) EndRdx(40) Acc(40) Empty(42)
32) --> Throw Spines==> Dmg(32) Dmg(42) Dmg(42) Rechg(43) Acc(43) Acc(43)
35) --> Oppressive Gloom==> DisDur(45) EndRdx(45) Acc(45) Acc(46) EndRdx(46)
38) --> Soul Transfer==> Rechg(38) Heal(46) EndMod(48)
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01) --> Power Slide==> Empty(1)
01) --> Sprint==> Empty(1)
01) --> Brawl==> Empty(1)
01) --> Critical Hit==> Empty(1)
02) --> Rest==> Empty(2)
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im gonna be teaming with a kin/achery defender all the way .. give a comment please