What a monster…
A simple spell like 'Lightning stun' could take over eight minutes which wasn't ideal during a battle with mana beasts. No mana beast would wait for an Elementalists to complete a spell before attacking.
It was one of the reasons why the Dark Ages were very tough. Back then, Elementalists had to struggle to cast spells.
They didn't have the luxury of "runic languages" or artefacts. All they had were guns and firearms which were pretty useless against mana beasts.
Seventy per cent (70%) of confrontations with mana beasts during those days led to death or the loss of humans.
People had to delay or stall mana beasts just to gain the chance of successfully landing a spell. Some even used their companions as bait, all to stay alive.
According to what Harry was taught in the academy, only about five to ten per cent of humanity were strong and resilient enough to survive the 'apocalypse ages'.