Sword-and-sorcery games have gotten short shrift in this book, so let's rectify that by using one to illustrate several ways of adding Rooting Interest.
Picture a rolling green landscape. There's a forest in the distance. Stick a few medieval villages over here, a castle over there, inject some trouble into paradise, and suddenly there's a gaping need for a hero like you.
The enemy, Alrik the Dark, has unleashed a wild, powerful dragon that has been passing time by barbecuing a few of the neighboring towns.
You enter the village and find it crowded with refugees. One in particular is terrified. It's a young woman, Serilda, who is descended straight from a line of powerful wizards. To protect her, her parents gave her up at birth. Thus, she walks the earth unaware of her own latent powers.
Because of these powers, she could potentially pose a threat to Alrik. Dead, her blood can be infused into his and make him more powerful.
The reason the dragon has been destroying town after town is Serilda. Alrik, through magic, knows she's somewhere in the land, but doesn't know how to find her nor identify her. She's the target that the dragon and the man who controls it (a henchman of Alrik) are seeking.
Though Serilda is normally strong, confident, and smart, these events would be harrowing for anyone. Having narrowly escaped death from the dragon once, and knowing that it's continuing its pursuit of her (although she doesn't know why), she's terrified.
Where will she turn? The villagers, learning that the dragon is after Serilda, have rightfully concluded that if Serilda dies, the dragon's path of destruction will cease. So, just as you enter the village, Serilda is being attacked by an unruly mob.
She's in grave danger, and we "feel for her." We identify with her.
Some might say that we would understand Serilda's plight but not feel for her. If the writing and animation are artful, you will. To use a film analogy, start the film off in a galaxy far, far away. Immediately introduce a small group of people in a spaceship being chased, fired upon, and boarded by shock troops from an Imperial Starfighter. The danger closing in on the small group causes you to instantly identify with them.