is there a way to reset lvl of ur units to start over all at lvl 1 or not ?
Afaik, you can't reset unit levels without losing all recruited units. Is there a particular reason you want to?
Umm in tags hidden by spoiler there is romance but in norm tags there isnt romance so... Is there romance
Yes, there is romance, but it's not your typical "fall in love" romance. The game is built on mind control and corruption, so this shouldn't be a surprise. Leon starts the game in a romantic (and very sexual) relationship with Anora and Noel, and all other relationships start with mind control rape and/or corruption. Every heroine has her own romantic ending with Leon.
Trying to read the wiki with google translate is melting my brain
Any helpful advice for team building on higher difficulties?
I generally just try get get as good of a null coverage as possible in the squad through any means, slap a defender in slot 1 with forward guard and have day/night attuned all over the units to keep the defense always stable, then get some decoy with target miss and, if possible, high evade in slot 6 on all squads I make. The rest are damage oriented, with barriers if i can have some.
There's a lot of teambuilding advice in previous posts you should look up for more details. Mixing and matching Night units with non-Night units is extremely discouraged. Even with the proper Attune skills, the Night terrain bonus/malus will still apply in absence of Terrain Null, and the most powerful Night divisions are synergistic.
If you haven't unlocked R7 Tactica (Truth, Ruin, and Destiny) or recruited most of the backer units, you should do those things first. High difficulty teambuilding is all about Nulls, Barriers, and Strat skills, and is much more flexible with better units.
Most teams have at least two attackers, at least one tank, and exactly one decoy. All divisions should have Absolute Cure and be protected from area attacks and flanking attacks at minimum, though some may not need Flank Null.
Pick your initial leaders for Surround Null, Terrain Null, or Fool's Lie. Useful formations (the ones that lower enemy skills) are a bonus. These will form your core divisions. Every battalion will have at least one of these, and you should be able to use most of them as standalone conquerors or defenders. After you have your core divisions, you can start building teams using leaders with Dimension Slash, Command, or Shell skills. Force revival divisions are a special case.
Pick tanks for their durability and devote all title and equipment slots to increasing said durability. Rely on other units for stuff like Null coverage. If you can't get to Hardy Physique 90 or Godly Physique 93, pick a different tank. If the formation reduces Critical Boost, Parry tanking becomes much more reliable.
Pick decoys based on your tank and available Nulls. Full tanks (Evade 100+, Godly Physique 93, and/or Slayer Defense 100) only need a decoy (with Target Miss if the tank doesn't have Forward Guard). Melee tanks need an Evade decoy (Evade 130+) and a source of Flank Null. If you cannot provide a Evade decoy, use an additional Evade tank with Forward Guard or a decoy with Target Miss in front of an Evade tank.
Pick support units to fill area Nulls, then prioritize Shelling > Strat > Self-D > Spell Barrier in that order. Keep in mind that you can omit any of these, but everything you don't protect against is something you will have to watch out for when deploying. Often, you will have to sacrifice absolute protection to include attackers so your division isn't a sitting duck.
Pick attackers that fit in with your mostly-built team and celebrate quietly if they match the formation. Always worry about attackers last. You will never run out of good attackers.