What's special about White Rats?

Solution 1:

There's another bone charm, "Welcoming Host", which grants you longer control over white rats using possession.

Source: IGN wiki

Solution 2:

I noticed that as I progressed (I just finished the Flood District mission) that there are a number of bone charms related to the white rats that may help understanding the Albinos charm you mentioned. The more charms that I found (and I don't have all these, the more the rats (especially white) started to figure into a bit of strategy/gameplay more and more. This is just info I got from the IGN / Wiki: Related Bone Charms:

Albinos - Increased chance of white rats appearing. Carrion Killer - Killing rats gives you some adrenaline. Rat Scent - Rats attack you only when you walk closer. Welcoming Host - Increased possession time for white rats.

These are listed as pre-order bonus charms, so I guess if you didn't, then you won't get these (not part of the standard list of in-game charms to be found)

Gutter Feast: When Corvo eats a white rat, he regains mana. White Rat Friend: White rats are neutral towards Corvo, not hostile.

Now, I did hear something on a YouTube video... the narrator said that when the rats attack, that by killing the white rats you will make them go away. Haven't confirmed that, I get so jumpy when that happens, I just try to get the hell out of there, lol.

Those pre-order charms are really nice, I wish they chose some others to use as bonus content.

Heres the 2 prepurchase bonus's that I could find: Gamestop Void Channel: Corvo's supernatural abilities last longer and do more damage Gutter Feast: When Corvo eats a white rat, he regains mana. White Rat Friend: White rats are neutral towards Corvo, not hostile.

Amazon: Fencer: Win sword vs. sword contest more frequently. Blast Resistant: Damage from explosions reduced slightly. Fire Water: Shot whiskey bottles explode with greater intensity.

All those are keepers and even with such a limited number of slots, I am sure I would have used a couple of those at all times.

Anyway, there you go.