Ktraken has the ability to swallow things making it very much like a PC who declares that they stuff the fire giant's sword in their pack/bag of holding. Your quibble over how a CR25 monster could learn the take weapon maneuver seems to be a purely technical dance to distract from the fact that anyone (PC or monster) using take weapon could stow the stolen weapon somewhere that makes it entirely unrecoverable. There have been quite a few who said this was a nonissue already so why avoid it in such a way?Take Weapon says you can take the weapon and spend two more exertion to use it. It says nothing about eating the weapon--which, since it's an edged weapon, should do some damage going down. Also, since maneuvers are learned abilities, not innate ones, you'd have to figure out how the kraken learned a maneuver involving weapons that are toothpick-sized to it.
Again you are bringing up technicalities in the example, Alice could have been a strength based fighter/martial/berserker/etc with a mere 14 dex & the overlooked herald extra saves wouldn't help. She could also be a herald who simply rolled very badly.Trolls aren't very bright, but I suppose they could learn stuff. Still, this is an outlier, and in your example Alice, who is wielding a holy avenger, seems to have a grand total +2 to her Dex save. Assuming that she's a herald, she should be getting a bonus to her saves equal to her Charisma modifier--which should be pretty high, because she's a herald.
Why are you assuming 4 guards? can the lich & trolls not be trying to escape from the PCs in an encounter that the PCs could be expected to handle. Does changing the lich to some other lower CR creature capable of casting dimension door like a (CR6 mage) not remove your complaint with the technicalities of the example encounter while still maintaining the problem? Why target technicalities of an example to dismiss it rather than the problem the example is used to illustrate?Also, liches are CR 21 and basic trolls are CR 5 each, then assuming four guards, that's CR 41, right there. By the time that this is anything other than an impossible challenge for the party, the Alice will have probably have lots of other tricks to help her retain her hold on her weapon, like expertise die.
She could, but if she's a strength based character those other abilities will usually rely on having a very nice weapon & if you need to resort to citing that inspiration could possibly allow a reroll it's shining a spotlight on the problem that the target could just use take weapon again the next time she attacks it. Eventually it will run out of excertion, but so will her supply of weapons.Even if she's not a herald, then she should have some other abilities--and possibly inspiration to spend on rerolling saves.