simply put, this ability is too strong for such a low cost, and to be constantly active. the reduced cost needs to be removed completely, along with the damage increase (since both of these would only happen if the REI/SEI stat was boosted, and stat boosting techs aren't allowed here). The sensory part is okay, but it needs duration limitation on it.
Oh, a five percent increase in spell power is a "much higher SEI"? Here I thought it just increased damage by a paltry sum as a triviality and reduced the cost of techniques. I must've missed that part where I shoved an obtuse, throbbing stat-beefer in there. How clumsy of me.
At any rate, with the changes you requested this spell would literally provide no benefit. It would be a very ineffectual sensory technique - I could probably make a separate technique for that if that's what I wanted, but it appears my choices with passives are very, very limited.
So, I changed it to being a weak defensive barrier instead. Probably what it should've been anyway considering what I put for it's type. This technique is required to use some other techniques, but without any effect beyond that it is essentially pointless and really discourages the creation of a build where one's techniques actively interact with and effect one another. At least permit the mild passive defense boost.
It wasn't just the damage, more so the actual control of the energy, which is based off of SEI. Having 20% more efficiency is like having a lot more SEI. it allows you to use that many more techs, because the control is so high. Now please, no more snide little comments like that.
"This energy is often sacrificed for use in other techniques," This part needs to be removed. You can't use the energy from this tech to fuel other techs.
20% could've been 20% more power, though in this case it was used to reduce the cost of techniques. When something is more efficient you either spend the same amount to get more bang or spend less to get the same bang as before. That situation was the latter, but it's history now.
"This energy is often sacrificed for use in other techniques" - I meant to imply the barrier is canceled if a technique which requires Lunar Raiment to be active is used. That is what this actually means. I thought that was self explanatory and did not imply a cost was being sidewinded, but I can make that specific if you prefer?