Imrod is perhaps the most straightforward boss fight in Mortal Shell but he is not without his challenges.
Cold Symmetry did well with the design of most bosses in Mortal Shell and even though Souls fans are certain they are not hard enough, casual players are likely to still get stuck on some of them.
If you are learning the ropes still, Imrod is probably the best boss to start with - his attacks and powers are well-telegraphed, giving you the perfect opportunity to practice dodges, parries and hardening.
Imrod's attacks and abilities
Charge: The boss runs at you and upon closing the distance swings his mace twice. These hits cause a lot of damage and set you on fire but the mace strike distance is not that long so just dodge backwards and you will be fine. Use spring with a heavy attack to re-engage immediately after.
Fire Breath: Cone attack that will set you on fire. Neither the breath itself nor the fire ticking will do too much damage so if you are confident you can avoid his other attacks, you can use the time he's spitting flames to damage him instead.
Double Strike: Swings the mace sideways. Dodge backwards, wait for the second swing to finish and then sprint with the heavy attack to re-engage.
Ground slam: Overhead slam with his mace. This attack usually follows up the Double Strike. If you re-engaged after the second strike, just use Hardening to endure the slam and then do a damage combo to get the most of the situation. Sometimes, he will just jump and do an overhead slam without the double swing beforehand. This one can be followed up by Kick.
Kick: This attack knocks you back and isn't obviously telegraphed so don't sweat it if you don't avoid it every time. You won't take much damage from the kick itself but make sure you dodge the flaming corpse Imrod throws at you afterwards.
There is no need to distance yourself too far from Imrod. His attacks are very powerful but they are extremely slow and easy to dodge or resist with Hardening.
As such, the best idea is to stay aggressive while keeping enough stamina in reserve for a single dodge. Each time he completes an attack, there will be enough time to throw in two or three attacks of your own.
Smoldering Mace and Withering Blade are slower so try to limit yourself to one or two attacks each time.
You can also make sure you have the best odds by getting your weapon upgraded to +5 by looting enough Quenching Acid along the way.