The Necromancer's Book of the Dead is a powerful tool that allows you to customize your undead army to suit your needs. There are three different specializations that you can choose from, each with its own strengths and weaknesses.
The Skirmisher specialization focuses on increasing the damage and speed of your Skeleton Warriors. This specialization is ideal for players who want to deal high damage and overwhelm their enemies with a flurry of attacks.
The Defender specialization focuses on increasing the health and armor of your Skeleton Warriors. This specialization is ideal for players who want to tank damage and protect their allies.
The Reaper specialization focuses on increasing damage and range of your Skeletons. This specialization is ideal for players who want to deal high damage from a distance.
To increase the number of undead minions you can have, you can use the "Shift + C" or "RB" button to open the character screen and choose the "Raise one additional Skeleton" option. These skills will allow you to summon additional undead minions to fight alongside you.
To make your Necromancer even stronger, consider investing in other skills that complement your undead minions, such as "Corpse Explosion". You can also equip gear with bonuses to the number of minions.