Marisa Fodder - Infantry Pulse

That depends entirely on what kind of units you plan on running in your team(s), so you would have to specify which units you have available or are viable as units you plan on further investing in.

In rough individual general, you can check the 'Skillsets that use skill' section on the page shared below to see which units GP staff recommend run that skill, but at the end of the day, it is the team composition that is essential, so you would have to specify your units.

Link to the page mentioned: https://fireemblem.gamepress.gg/passive-skills/infantry-pulse-3

It's more team specific than hero specific so I would just recommend making an actual team around the skill and then giving it to the person on your Infantry Pulse team that needs it the least.

As for recommendations, someone like Ephraim, Brave Ike, Seliph, and Dragons (namely Ninian), whom all have high HP and can all manage their own special charges without help or don't need to manage their own special charges are very good candidates.

As for who could make good use of a Infantry Pulse teammate, Blade Tome mages and defensive brawlers who can utilise Ignis/Glacies are fantastic candidates for receiving the reduced CD, this also goes for units who heavily rely on and/or utilise Wo Dao and Slaying type weapons.

Marisa

I’m giving infantry pulse to chrom as he has base 47 HP. Bartre, Fae and many other high HP infantry units make good use of it.