This image shows the different look of a dragon cemetery and a dragon altar.
These are the basic unit at a Dragon Altar. The number of resources is always 1000 each. After a battle, the victor can steal the 800 of each resource.
In the very beginning of the appearance of the altars, I used to send a very large troop- 20k squires, 20k Templar, 8k battle mages, and/ or 5k of other elite troops. But nowadays just lesser.
Sometimes just a 3-4 types of soldiers sent there.
And sometimes to send the battle mages along.
The aim of attacking a dragon altar is - frankly speaking- to obtain the wood chips (Elf Wood). They are exchanged for dragon scales on the ship that would sail to the dragon island. Later on that :)