One of the most essential aspects of a fight between mana users was how much energy they could gather and accumulate at any given time to fuel their abilities. Because an Elementalist's ability to control was usually greater than the amount of mana they could store within their bodies, using more powerful capabilities required a longer cast time, during which the user gathered as much mana as possible from the atmosphere.
To emerge victoriously, one had to constantly overpower the opponent, preventing them from gathering any additional mana and eventually depleting their mana pool.
Desmond's opponents followed this ideology throughout the battle, constantly harassing Desmond with all sorts of attacks, trying to eventually wear him down and corner him.
The invading soldiers made a massive mistake in all of this, as they completely ignored a self-explanatory item on the battlefield; the barrier of water behind Desmond.
