Blocking and defense rating in Median XL work much the same as in classic Diablo II Lord of Destruction, but their role in the game has changed. In the regular game, max block (75% block) through investment into dexterity was common, while defense rating was hardly worth it. The two statistics are much more balanced in Median XL.
Important: In Diablo II, when you run, attack always hit you and chance to block is reduced to 1/3. Walk speed is much improved in Median XL though, so you might consider walking.
The chance to be hit, when walking or standing, is as follows:
Capped between 5% and 95% and rounded down
Investing into defense pays off if you can get around 75K defense at level 120, at which point you will see a noticeable improvement in your chance to be hit. Some builds can go well over 500K defense.
In Median XL, your base chance to block depends on character class: * Amazon, Assassin, Sorceress: 3% * Druid: 2% * Paladin: 1% * Barbarian, Necromancer: 0%
Shields have 0% chance to block, except class-specific shields – which provide +1% extra chance to block.
The block rating is boosted by dexterity as follows:
Capped at 75% chance to block, rounded down.
Max block is hard to reach; you will need to invest heavily into dexterity. This is a balance measure in Median XL to ensure that shields do not outclass two-handed weapons as in classic Diablo II Lord of Destruction.