However, you can gain a lot of mana from leveling up and from equipment, so, depending on your expertise, you can actually invest less than you think here if you know what your doing.

Diablo 2 Energy - Energy is all about Mana in Diablo 2 and essential for magic characters to cast spells.

Diablo 2 Vitality - Vitality boosts life and stamina and is basically worth investing in for almost any character or build.

It also improves your chance to block with shields.

Diablo 2 Dexterity - Dexterity in Diablo 2 largely revolves around improving your ranged abilities, increasing your accuracy and is a prerequisite for most ranged weapons.

Damage wise that's mainly for melee characters - increasing weapon damage for each point you invest - but even magic uses will need some strength to be able to use some of the heavier armor. Summon necros of course, but bone necros are even more powerful. You mention hamnerdins, they dont solo diablo, they 1 shot him, and every other enemy in the game.

Diablo 2 Strength - As the game says, this lets you increase your attack damage and equip more weapons and armor. Every class/build can, diablo 2 is insanely easy.

But what do the main options of Strength, Dexterity, Vitality and Energy do? There's no point putting all your magic character's stats into strength, obviously. Whatever character you pick in Diablo 2, it's important to spend your points wisely as you earn them. Magically they can use fire and wind spells, transform into animals (like a bear) to fight, and summon all sorts of plants and creatures to fight for them.

The Diablo 2 Druid class is a good one if you want a jack-of-all-trades as they can take a beating like the Barbarian, put out damage like a Sorceress, and summon companions like a Necromancer.

Best solo class diablo 2 resurrected