I see that in the Eastern Empire we have dragoons, lifeguards etc. So in my twisted mind I thought, why not grenadiers? The obvious problem is that there is no gunpowder. But there is magic! I did not want to put too much work into this if there is no appetite for it but here is a rough outline:
Grenade: An offensive spell that can be quickly deployed. These spells are usually contained within scrolls and in some cases other magical devices, seals, runes, or sigils and do not have to be wielded by trained wizards, mages, etc.
Grenadiers/ Horse Grenadiers: Grenadiers are specialized military units trained for assault operations. Their primary weapon is the grenade. The trade requires literacy and the ability to speak clearly in Common and at least one elf tongue. This is necessary because the most common “grenade” is a scroll that must be read aloud or sung and each word clearly enunciated. Grenades can be some of the most dangerous spells as they are often both hastily conjured and used. Making them more dangerous is the fact that the person using the magic is nowhere near the person who made the magical item – if a spell fails or backfires, it is thus of far less consequence to the mage who created it! Because of these inherent dangers, unlike battle mages who may fight from the rear echelons or behind the protection of pikes or fortifications, grenadiers are often deployed at the forefront of an attack. They thus must be of a courageous, desperate or foolhardy character and be in outstanding physical condition.
A note on scrolls: Scrolls are the most common type of “grenade”. They are spells trapped in parchment that are released when read. They are usually written in verse or into music where the meter or tone is critical to trigger the spell to avoid it being accidentally released. Moister can ruin parchment and cause the magical pigments to run thus limiting their use in rain, snow or high humidity.
Anyway, hope this is of some value
This is a clever thought, but in Lys the heavy cavalry of the Husaria still reigns supreme upon the Fields of Honour. Battle Mages tend to be used more in the role of shock artillery, or to send ensorceled objects hurling far downrange with the help of artillery. And of course, to counter the casting of the enemy mages. Under Lys doctrine, the infantry is primarily a defensive unit, to provide support to the cavalry and protect artillery, camps, and key locations. Also, frankly giving such powerful weapons to peasant infantry levies, would probably be extremely unpopular with the aristocracy...
But there certainly could be a nation out there which uses such trained infantry. It could certainly make sense for the merchant-nobles (magnates) of The Lowlands, who can probably afford to pay for such weapons to be made, and who have a larger middle class from which to draw educated infantrymen to fill these roles, even mercenary soldiers. And lacking a more traditional aristocracy born to horse riding, it could be a more suitable army for them to rely more on infantry.
So this may yet be of some value!