I rolled a 1st life drow for kama twf ninja spy, but found myself hardstuck on An Invitation to Dinner. I used my lh to reroll into a shuri thrower, but it dawned on me that shuriken, like bows with zen archery, do not actually generate ki. How can 10k stars, shadow double, flashbang without the ki gen? Do I just ignore flashbang and shadow double completely and save 10k stars for bosses?
Others have noted stuff. But thinking like a ninja and not an archer is important here.
Max out "Stealthy" enhancement and add skill points to Hide and Move Silently. You are a ninja. Act like one and, with enough Sneak Attack, your first strikes against many enemies will be few or one. You NEED to Sneak to get Stealthy's +1 passive ki regeneration. Sneaking DOES work, and you can avoid many fights, especially in older quests, just by sneaking. Newer quests have more "gather" and trigger points but stealth is still very viable.
Maxing out the Mystic tree's Contemplation gives you another +1 passive ki regeneration. (It's location might have changed with U72.)
By level 12, staying in Ocean Stance will also give you not only another +1 passive ki regeneration but also higher Dodge and saves. falconry's attack DCs are based on your WIS or highest stat, I think. Make sure DEX and WIS are higher, and Ocean Stance adds to your WIS.
A starthrower is a one-trick pony. But with Falconry enhancements, you can trip, blind, and assassinate. You need to put only enough AP in Ninja Spy for maybe three Sneak Attacks, Stealthy, Sting of the Ninja and core 3 for Shadow Veil. Action boosts for attack is fine. But just time your attacks so you need Ten Thousand Stars and boosts only during boss/minibosses and you'll be fine.
You'll have plenty of ki if you change your playstyle to NOT always fight or to use quick takedowns with bird-trips. Granted, the undead won't get critical hits, but a Barovian weapon doesn't care with all its damage.
Also, a lot of people want to get Improved Precise Shot. You don't necessarily need it if you give yourself a modest harassing party attacking ahead of you. Precise Shot's Archer's Focus really gives extra damage to the point that a good defense means few things ever reach you. There's a sweet spot in how far you are from enemies. Too close and they all jump on you. Too far and you might have a hard time targeting. Until you reach Epic levels and use Shiradi effects, using IPS in Heroic could be dicey. Hit too many targets and you'll be mobbed.