Either type in /join portalundead or get to it through the main questline (and your Book of Lore!)
Chat with our AI personalities
i
to get the undead pirate curse armour u need to have another undead armour
You cannot get the Undead Warrior without ACs, sadly.
To obtain the Undead Commander's Sword, you must keep fighting the Undead Giant until you manage to acquire the sword.
You can buy it from Arryd in DoomWood forest (/join doomwood) for 10750 gold.