+25% faster casting speed

One of the good reasons why a caster or Hammerdin (paladin who uses the Blessed Hammer ability as his main attack) might want to use the Fortitude runeword.

+300% Enhanced Damage

Good damage from a weapon runeword, but there are other runewords that provide a bigger damage boost (Doom, Breath of the Dying, Grief, etc.)

All Resistances +25-30 (varies)

Regardless of whether you create this Runeword in armor or weapon, you get a nice bonus to All Resistances, which is always very important to have in Diablo 2.

+200% improved defense

This is the only mode that offers a strong incentive for any player to use Fortitude.

It’s a good mod to have on a Fortitude body armor, but it would be an even better mod when it appears on the Fortitude weapon you create.

Why?

When you create Fortitude in body armor, the +200% Enhanced Defense is applied to the Defense of the armor in question. However, if you build Strength into a Weapon, the +200% Enhanced Defense is applied to Total Defense (armor, plus helmet, plus gloves, plus belts, plus boots, plus shield, etc.).

20% Mortal Blow

Hit causes the monster to flee 25%

These two weapons appear in a Fortress Weapon.

Deadly Strike in Diablo 2 gives your character a X% chance to deal double damage.

The second mod is not very popular with melee characters, because most characters that engage in melee combat want the monster to stay still, which makes it easier to hit it. However, Hit Causes Monster to Flee finds some popularity with builds that use ranged weapons, as they would need to keep the distance between themselves and their targets as large as possible.

Resume:

Fortress requires Lo, an extremely rare Rune, but looking at the stats, it could very well be worth its high asking price. Fortitude seems to be more powerful if used on a weapon, since the defense bonus would be applied to the total bonus, rather than just the bonus from a Fortitude body armor. Not only do you get a 200% bonus to total defense when using a Fortitude weapon, but if Chilling Armor activates during combat, you get an additional 115% defense bonus, which should make your character very cool. , very difficult to reach.