Although Lin Li had transmigrated, the so-called tactics in his mind were just a 16-character guideline for guerilla battles which did not play a significant role in battles at all.
As the Highlord of the High Elves, Osric had once led the Magic Legion around and waged wars countless times, and could definitely be considered a master of strategy and tactics.
Although Lin Li refused to give up, and was continuously injecting his mental strength into the control crystal in a bid to win using his combat strength, Lin Li gradually lost the space his troops had because of Highlord Osric's continuous devouring. Eventually, he did not even have room to stand.