Currently I am Level 58 playing as Maya the Siren. I have been building my skill tree to try and get the Ruin skill active. I have the full 5 in Reaper but now find I still need 5 skill levels in Phoenix Blight before I can get Ruin active.
Is there any way to activate Ruin without having to go through Phoenix Blight?
My full Cataclysm skills are 1 in Flicker; 5 in Immolate; 5 in Chain Reaction; 5 in Foresight, 0 in Helios; 0 in Backdraft; 1 in Cloud Kill and 5 in Reaper.
Thanks
knighm
You don’t need or want Blight Pheonix, as long you have points above it counts towards the 25 you need to get ruin. What class mod are you using? That usually determines if you want Flicker or Helios for the extra points. The following assumes you are playing co-op, but should be fine. We don’t have the points for life tap yet, so the Leg Siren v Leg Binder setup difference doesn’t matter yet.
http://bl2skills.com/siren.html#505001500005050100004550510501
If you have something boosting Sweet Release, you can go 1 point there with the rest in the irrelevant Mind’s Eye skill.
Yes, add a few points to Helios to get to 25 total in the tree, which unlocks Ruin. This is what my Maya looked like at level 58. Feel free to move points between Flicker, Immolate, and Helios as you see fit as long as those three skills sum to 9. Until/unless one has a Legendary Siren COM, the point in Flicker really isn’t doing anything, for example. If you play co-op, go ahead and move a point from Sustenance or Elated to Res. And maybe a point into Restoration as well if you do a lot of co-op.
If you’re playing UVHM without Ruin, you should definitely respec immediately to fix that. It’s a hugely important skill!
Pretty much the same of course since most standard Maya builds are similar, I heavily favor Intertia over Elated however. After a kill is when you most likely need to reload and that extra reload speed is really useful to move to the next kill.
Mostly a matter of what order to take things. 
For me, 4/5 Inertia is the level 72 skill point, since I wanted to get Life Tap and Scorn first. If somehow a character was to be stuck around level 58 (maybe the level 61 cap for people without UVHM2), yeah, favoring Inertia over Elated makes sense.
Yeah, Life Tap and Scorn are great, but you can always respec and it’s rare that you would gain 3-4 levels without the opportunity to do so, so that’s why I was suggesting Inertia now, then when he has more points he can respec and get Life Tap and Scorn.
Ruin and/or Scorn are usually vital skills in any Maya build. Scorn benefits from Flicker, so if you have a hard time deciding between Helios, Flicker and Blight Phoenis, then Flicker would be my recommendation. Whether Flicker actually does anything has been discussed here several times, but I’ve tried with and without it when using Scorn, and I’m convinced. Scorn benefits from Flicker.
Ruin is basically a guaranteed slag on the enemies, so it’s definetly worth specing 5 points in a skill you don’t really want in order to get to Ruin.
For me, I prioritize Converge over Scorn so I would take Scorn later near max level. Ruin is essential so that’s 26 automatically allocated, plus another 11 for Converge and 10/11 for Wreck/Res and then one can go further down the Harmony tree. For where the OP is at, I think Inertia makes the most sense as he can respec to go further down Harmony when he has more points.
I normally take Helios over Flicker but it depends on class mods.
Converge has priority over everything! 
For any build of mine, if I got down the cataclysm tree it always looks the same. With the exception of one point in flicker if i had a siren mod, but I don’t.