The Chariot in the Thoth deck has a specific role to play in the alchemical story told by the deck’s major cards. I won’t go into further detail here, except to note that he is carrying the Holy Grail. 🙂
Further details may be found in Lon Milo DuQuette’s excellent book.
Crowley describes the card thus.
Triumph, victory, hope, memory, digestion, violence in maintaining traditional ideas, the “die-hard”, ruthlessness, lust of destruction, obedience, faithfulness, authority under authority.
I like the idea of this card as a herald. A new force comes into the picture, and melts the old forms.
May the reformation commence.