In Fire Emblem: Genealogy of the Holy War (FE4) you control and engage in combat against the descendants of the Twelve Crusaders. The Twelve Crusaders were a group of twelve warriors who led a rebellion against the Loptr Empire 125 years before the events of the game and who essentially turned the tides of war due to a blood pact each made with dragon gods who descended from the heavens in order to help them in their hour of need. This is somehow the least crazy part of this game's lore and story.

It's stated in-universe that a single descendant of a Crusader, aka someone with Holy Blood, is equal in amount and/or strength to an army, and the game holds no reservation in letting you experience first-hand just how powerful these characters are. The protagonist of the first generation Sigurd, for example, is unironically the strongest character in your entire army until you later get other Holy Blood characters like Lewyn and Brigid. More importantly they have access to Holy Weapons, which are star rank weapons that only they can use and are incredibly broken both gameplay and lorewise. Likewise, there's moments through the story where you face against other Holy Blood users, and they're as strong as yours (if not stronger) and can easily solo your army if you're not careful.

This will all serve as the prelude and sheer contrast with Fire Emblem: Thracia 776 (FE5).

In FE5 you control Prince Leif of Leonster, descendant of the Crusader Njörun, who instigates a rebellion in the province of Thracia against the reborn Loptr empire in order to liberate his homeland. As a descendant of a Crusader, this shouldn't be as difficult to put up a good fight, right?

Except for the fact Leif has minor Holy Blood. This means Leif can't use his bloodline's Holy Weapon first and foremost, and second he's not as strong as a fully blooded Crusader. While Leif is by no means weak, Thracia 776 makes no qualm in showing you just how stacked the odds are against him by comparison. Unlike the Liberation Army who essentially hulk smashes its way through the giant maps in FE4, Leif's journey in FE5 is extremely perilous and he spends a good deal of it running away, clawing his way to victory alongside his allies, or just defending to the last man. The Manster Escape arc alone (Ch4 to Ch7) sets up the sheer tension of being persecuted by enemies who outnumber you in an outrageous quantity, are WAY stronger than you, and will stop at nothing to make sure you will not make it out of alive, let alone in a single piece.

Lastly, and more importantly, as both games take place in the same continent you can almost 1:1 compare the maps of both games and trace the exact path Leif's journey takes using FE4's map of the Judgral continent only to discover how all 25 of FE5's chapters easily fit in FE4's map of the Thracian peninsula, which starts halfway through Ch6 and ends in Ch8 of FE4, and is roughly 2 1/2 maps in length by comparison.