"The Grenadier is a big and powerful ranged unit that deals area damage - rather inaccurately! Be careful about sending troops in front of him, as they might get caught in a grenade blast."
Summary
The Grenadier is unlocked at Headquarters level 16.
He throws grenades that can do splash damage.
His throws are very inaccurate but can be very long.
The Grenadier is a bulky, middle aged man, with a moustache who wears a thick green vest with a bandolier of grenades that he throws and a blue beret.
His uniform underneath the vest appears similar to the Rifleman's.
Offensive Strategy
Although the Grenadier's range is shorter than that of Sniper Towers and Boom Cannons, their inaccurate shots and splash damage allow them to attack these defenses without getting hit provided that they are targeting another building. Therefore, it is not a good idea to directly flare onto defenses.
Grenadiers and Medics are a good combo, because the Medics can outheal the damage done by Rocket Launchers.
The Grenadier's grenades usually overshoot the target but never undershoot. Thus it is generally not advised to use this troop with Warriors because his grenades can hit them. Zookas do not work well with them, as they are incapable of tanking both Sniper Tower or splash defenses' damage.
You can use the Grenadier to pick off Flamethrowers and Machine Guns that are unprotected by Sniper Towers, Rocket Launchers and Boom Cannons, because neither the Flamethrower nor Machine Gun will be able to hit him. Note that this method is slow if you have only a few Grenadiers; you might run out of time in the attack.
Some players use them as minesweepers and deliberately avoid upgrading them to do less damage to friendly troops.
Because the Grenadier does area splash damage, it is not advised to group Buildings together.
Do not place Economy and Support Buildings in front of your defenses; when Grenadiers are attacking these buildings they usually overshoot and hit the defenses instead, usually without counter-attack from the defenses.
Placing Sniper Towers in front of all your buildings and your Mines spread-out in front of the Sniper Towers is a good way to defend against Grenadiers.
Upgrade Differences
There are no visible changes between levels, but each upgrade increases the Grenadier's hitpoints (by 6%), DPS (by 7.5%), and training cost (by 1000 gold).
Trivia
His beret suggests special-operations training.
The training cost of a Grenadier is the same as a Tank of equal level. However, since a Grenadier has fewer unit size than a Tank, it's the most expensive troop to fill up a fully upgraded set of Landing Crafts despite having fewer levels than Tanks (544,000 gold for maximum level Grenadiers; maximum level Tanks' 528,000 is a close second).
The February 2015 update made the Grenadier attack faster (therefore better at minesweeping), but each attack does less damage, keeping his DPS unchanged. His attack range is increased by a small bit.
The Grenadier, along with the Scorcher, are currently the only two troops that can damage friendly troops.
