Level 1
+10% ramming bonus for all units
+2 zeal
Level 2
+4% melee attack skill for all units
+4% shots per minute for all units
+20% ramming bonus for all units
+3 zeal
Level 3
+8% melee attack skill for all units
+8% shots per minute for all units
+30% ramming bonus for all units
+4 zeal