If you really want to, you could probably make spirit bane: watchers work, if the character is mundane. A mage can too easily dismiss *most* of a watcher's hijinks. But you can still give it a try if you like. The trouble is, watchers aren't dangerous, just a nuissance... most times.
Spirit Bane: Fire Elemental, for instance, is quite dangerous. A single watcher is not. To make up for this, you'll need to make watchers nearly omnipresent. Even a hundred watchers at once can't do anything physical to a mundane. But a hundred watchers in a month could really mess with a charcter. They key, as I said, is that you need to find a way for watchers to be around
constantly Being, as some believe, partial and weak manifestations of a summoner's will, you may decide that Spirit Bane: Watchers means that the watchers are actually
summoned by the character's flaw. Some random quirk about his personality makes him unconsciously summon watchers that hate him. perhaps it's a deep-seated self-loathing or whatever. Whatever it is, it means watchers can show up anywhere, at any time.
Anyway, once you find an excuse for practically continuous watcher presence, here's a few things to make him eat those 10 points:
Step 1) Sleep deprivation and edginess. Watchers show up in the dead of night, EVERY night. Some nights the one-watcher deathmetal band starts playing, other nights maybe they put on an act or two of "most annoying and loud arguments ever performed on stage." The character will have to sleep in powerful wards to avoid them. If the charater himself is summoning the watchers in his sleep, well... even wards won't help. Watchers should constantly pop out of places they aren't expected -- cereal boxes, ammo bags, etc. with scary faces. They can manifest on top of things like food, and make it look spoiled -- or like a severed head. The character should be poorly rested and jumpy.
Step 2) aggravation. Picture watchers as the most annoying children EVER. The only benefit is, you can zap them... but they'll be back. "Watcha doin? Whatcha doin? watcha Doin? What... cha... do...In? wathca doin? watcha doin? WHAAAAAAAAtcha doin? *team mage walks up, **zap!** *" -- this even works with mage characters in public places. Don't want to go around advertising dangerous spells and the like, so you'll have to get the annoying watcher child to follow you into a dark alley somewhere. Hope it's not SO dark that someone mistakes it for a real child (unlikely, but the character might still worry about it)
Step 3) An end to social life. "Hey, you know as a spirit I can read his mind? He only wants one thing, you know. And you'd better not leave for the bathroom, he'll sick you with the bill. Seen him do it a hundred times. But really, with that mole on your face, I wouldn't worry too much. He probably doesn't find you attractive enough to even use you." -- Best done as a whisper in his date's ear, so that he doesn't even know what happened...
Step 4) No stealth, ever. *dun dun dun dun duuuuun dundundundun* "Jim, what the hell is that music?" "I have no idea, but it starts up every time I start sneaking around! Sometimes, there's even a giant flashing arrow over my head, it's horrible!"
Step 5) Obfuscation via manifestation. Characters don't have much control over how their spirits, including watchers manifest. They can't, for instance, have a spirit of Man look like a lone star cop to get them out of trouble. But presumably, the spirit itself must have SOME control... "Jim, you're late, again!" "Sorry, suddenly my windshield went all black. I barely got the autonav on before almost plowing into a truck!" or have the watcher manifest as a hundred little smartlink reticicles drifting about when the character is trying to shoot something. This step isn't
entirely within the rules, because as I said you don't' normally get to use the manifest power as a "minor illusion." But I doubt the rules took into account the possibility of watcher bane either...
Step 6) Enemies. Once the watcher horde learns of the character's enemies, they can ferry messages to them pretty much at will. Watchers have that wonderful "search" power... which makes tracking down the character's enemies easy.
Now, if the character is mundane, the team mage can help out with a lot of these... but he can't be on guard 24-7. And eventually, the teammates will take care of any slack in the harassment -- no team wants someone around that is as big of a hassle and security risk as this guy will be.
Of course, the flaw is only 10 points, so you don't want to OVER do it. Having every detail of a character's life reported to every enemy he ever makes is way more than 10 points. But watchers aren't very bright, just creative. Most probably won't think to pull something like that. But... every once in a while, a character's enemies will be told by "a little birdie" of a meet, and show up to ruin the runner's day a surely as a pissed off fire elemental would.
So, anyone want to take this flaw in one of *my* campaigns? It's starting to sound like a lot of fun.