2smallest: This was determined empirically :)

Everyone knows that the direction of attack for dragons does not match the direction we set.

So, there is a general rule for attack. Each unit occupying one hex has two types of attack: main and "from the flank" :) Here, everything is simple: if the unit cannot perform the main attack, it attacks from the flank.

Two-hex units also have an additional type of attack:
D--O
--G-O
D--O

G - "head" of the creature, O - main attack, D - additional.

The order is as follows:
1. Main attack;
2. Additional attack;
3. Attack "from the flank".

Using these rules, you will never make a mistake with the direction of attack of your dragons.