Infinite kick is probably one of the best skill a twin has for an offensive move and could be potentially spammed if executed correctly with other skills. It has a 360* aoe hit box with a vertical distance added letting you catch players above your twin or even catch an archer about to cast or already casts shoot down. Especially if you weave since your twin won't get knocked up. Also it can be used when frozen letting you lock for a decent amount of time without even doing anything. In pve you don't even need to know how to use it, just pretend it's a small aoe 11 hit combo. Although on bosses you may want to mash x while the twin kicks.
Just a little thing almost every twin skill is practically a solid small aoe that has a solid knock down like broom jab. You can hit players behind the twin with skills if close enough, you just have to be near it to get hit. That's why I would disagree with the con of having no AoE 360* skills. I have seen twins in 85 catch 6 players with 1 infikick, and I will tell you now that people in 85 are probably smart pvpers so it's a decent skill in general. I don't see a pally walking in and catching 5+ people with a single bear or cross cut and those skills are generally seen as an aoe skill.
As for the first persons comment you don't have to press fusion to cancel skills. You can be an effective pvper by doing the right thing at the right time. If your twin gets knocked down or launched-> use fusion. If your twin is totally blind and is infinite kicking nothing-> use space bar or charge attack to recall twin instantly without having to use the fusion animation.
As for ring of hell, I only use it in F7 or pvp(fancy combo). I don't recomend getting it unless you want to look cool instead of infikick+x spam someone to death.
Release fighter force is the only reason why I play twins. Just my totally biased opinion, would totally 10/10 if I could. I love this skill more than... Well I'll just leave that to your imagination.
And for PvP stacking your'e doing the right thing. Health,movementspeed, and attack speed are the top stats to stack, next to resists and attacks.
And for pve+pvp I would recommend hero pos weapon. Socket min/max 10% Patk card, soul craft min/max Patk(or even Matk if lucky to have more) if your going all out. Assuming you have 3 6* atks and 2 cerb solars. Then again pos in general does more damage than elga in pve so you would use that anyway.
Belt is from ryvius you mentioned is from the purity set. Ryvius belt of purity.
The earring for ryvius is called verdure for the 10% mspd 1 piece. Add ring for a 2 piece atk spd boost.
Lava ring should be 5* for the movement speed.
Perseverance Aram earring gives 8% mspd/1.1 final critical rate.
And so on, I know you want to just shorten your guide on the equipment part, but detailing which part to get might be helpful to both old and new players just to freshen up the mind.
Great work on the guide, hope to see it updated more and more.
Thanks for your response! Well to be honest I wörter this guide when I had not that much experience as I have now with the twin so some parts need an update.
For the equipment part: I'd love to update it but I can't.. I always get an error message, even if I try to write just one word after deleting all. Until now nobody could help me there.
I use Rokko Expert medal for the moment. Thanks!
Super helpful, keep the work up! 
Anyway, i have a question about pet. I just got my own car pet from Xmas reward, and i just got it crit dmg and atk spd +3.0%. is that good enough? what pet stat would u recommend the most? And can i get some clarifications on agility stats for this class plz. And i'm PVE I build
