Grail

In my opinion, it depends on which faction you're playing... Colossus - +2 to morale is almost always useful, unless you're playing as Undead and don't have leadership. Spirit Guardian - same as above, +2 to luck is always helpful (except when you already have that skill). Sky Ship - I don't like it when the entire map is revealed immediately; I lose interest... Fire Elemental - well, if you're going to wander around the map collecting Imps (with Diplomacy), then it's a decent bonus, but otherwise, it's not very useful, especially if you're not the only one playing as Inferno... Soul Prison - when playing as Necropolis, it's very useful... Earth Guardian - a +12 spell power bonus is quite noticeable, even if it's only when defending this castle... Banner of War - same as the Earth Guardian, but for attack... Plant - +10 to attack and defense, like the two mentioned above. Although +20 defense would be more suitable for the Swamp. Rainbow - even though it gives you all the spells, by the time you find the Grail, you already know everything you need. So, in my opinion, it doesn't have much value... P.S.: I voted for Soul Prison.