Pets and you.

[Steel DarKnight]

Hit Points and Maximum Stats of several common and popular pets will become diminished Hit points on monsters used to be the equivalent of about 1/2 of a player's hit point, due to peculiarities of how UO's combat engine worked. In other words, if you hit a player with 0 AR and did 35 hit points of damage, the same exact attack on a monster with 0 AR would do 70 points of damage. Age of Shadows' combat engine does away with this dual method of handling damage, effectively doubling the worth of a hit point on a non-player.

Taking into consideration all of the combat changes including resistances, new damage values for spells and weapons, and additional factors, monsters' hit points were generally reduced by about 40% (with some specific tweaking to particular creatures). The end result is that creatures will still be able to absorb about the same amount of punishment after AoS as before.

Monster hit point numbers are now smaller, but the scale has changed. This is not a nerf -- it's just an adjustment to the numbers to keep monster power the same while the combat system itself changes.