This deck was built for the sake of "Expected Development" Hitagi. It's a strange looking card having the early play condition of having 2 green and 2 red cards on your board. This makes it hard to play, and costly if you try to play multiple copies in one turn, and I love it. A couple things to take note of here, none of this would be possible (or worth it) without "Tiger-Striped Hair) Tsubasa. It bonds to the Hitagi (pay 1) and gives it 1k power. So on level one you will start building a wall of 10k attack beat-sticks that will force your opponent to burn an uncomfortable amount of resources to deal with while you focus on your lvl3 game.
Hard mulligan for those tiger-stripes!!! You may have noticed I opted to run "Girl Who Could Not Be Left Alone" Hitagi. This is because it is one of the few red cards that I can almost guarantee will survive. It's going to be important to have at least one red card stick to the board for your level 1 early play condition. "Overall Happiness" Mayoi will usually be used to find Tiger-stripe, and sometimes "Doing Things For Future's Sake" Hitagi. Just make sure you have the bare minimum of one stock going in to level 1. It may be rough, the 0 game here is really weak, but we're playing the long game remember? Get experience 2 at the very least, and make sure you can play red.
Breathe a big sigh of relief as now the hard part is over. Hopefully it wasn't too hard and you've amassed two copies of tiger-stripe and found a future's sake. You of course don't need the early plays in your hand since they bond, so if you have the stock for it you can purposely pitch them while using future's sake's effect. If everything worked out, you should be able to play one of them. I don't recommend crushing cards to play more since that's going to put you at a fairly big card disadvantage, especially since we also run backups. The "Morning Sight" backup will give 2k to a red character, which should be most of your front row. So now it's time to just relax and be a wall, with the tiger-stripes in the back and your backups your opponent is staring down a 12k wall that can't be change punished, level reversed or hit with one of those annoying AOT cards that kill cost 0s. They can be bounced, but they only cost 1, no biggie. Make sure you have at least experience 4 going into level 2, you want either green or yellow.
Honestly not much more to do. Hey, now you can play your big guys unconditionally. Seriously this is usually so unstoppable that you can just ride it to level 3. But now you should be thinking about what you'll need. "Uroboro's Cat's Cradle" will be replacing your back row soon, but it's definitely not vital (unless the cx combo screws your opponent). If you can get "Good Luck Charm" Nadeko out, it's a strong pick. Remember it can proc it's effect on your opponent's turn if you save it with a backup. "Do It and Not Regret" Suruga can be early played, but try to save her as an assassin for your opponent's big guy. Try your best to find a copy of clown glasses, this card will save your ass. But "Serious Face" Hitagi is almost always the best choice. She does damage and gives you a chance to draw into event cards. Make sure you have experience 6 going into level 3. Try your best to have all three colours active, but if you can finish the game with just red green, don't feel you have to throw anything vital in the level zone.
It may not be easy to find exactly what you needed, but this deck has lots of nice finishers. Hitagi and Mayoi make a neat combo since shot can be applied to either the effect or the attack damage. Of course Tsubasa's card is fine on its own, but it's risky using it without Nadeko in your back row.