In Breath of Fire II is entered by obtaining the Therapy Pillow in Tunlan. Ryu and his team would then enter Dreamland by returning to Gandaroof. The group will then be taken to a land filled with monsters and three towns. One town is filled with children, one with adults, and one town with elderly people. There is also a tower called Memory Tower.
While exploring the towns you can find shops and a few people that will give you information on a few things. In the three versions of Inheart you can buy items and use the inn. You learn that a Demon attacked Memory Tower, messing things up, and that there are only supposed to be two towns.
Ryu makes his way to Memeory Tower and ends up fighting the demon at the top who has been messing with Gandaroof's mind.
In Breath of Fire III, Faerie Village is introduced after you fix the lighthouse in Rhapala. When you fix the lighthouse in Rhapala, one of the faeries appears before the party to attempt to turn off (or break) the lightbulb that the lighthouse uses. Since that fails, she insults and condemns the party for fixing the lighthouse and gives them the Faerie tiara (which is the only way to get to Faerie Village). She tells them to use it over a ring of flowers to get to their village and fix their "dolphin" problem. Once the party kills the dolphin, the faeries allow you to rest there for the night. Afterwards, the party leaves and are welcome to come back at anytime. Despite this, you can't really do anything there until you come back as an adult.
In Breath of Fire III, Ryu's Dream (or heart) is a place that can only be visited once in the game, since the only way to get there is to confront Teepo at Eden after you are adolescent Ryu. After Teepo fails to convince you to join him he shows you whats inside your heart and whats inside the hearts of your companions. It is maze-like but pretty straightfoward.
The Dreamland is first accessed during the events that take place in Wychwood. Ryu and the others encountered faeries here already earlier when they shrunk Nina as the party was passing by. Later in the story, they are sent here to procure a Faerie Drop for Blacksmith in order to forge a copy of the King's Sword. The faeries ask them for help in order to exterminate monsters that inhabit their home. The party subsequently enters the Dreamland to slay Fantam and his offspring to return the land to their rightful owners. This unlocks the Faerie Village minigame.
Deis, an Endless, has been sealed away inside the moving armor and Ryu, Nina and the others need to free her. They make their way through the dream sequence and eventually reach the place where the goddess was sealed.
Four pillars are binding her and those need to be defeated to free Deis and unleash the true innate potential of Ershin, potent combat magic. The party valiantly slays those pillars and frees the goddess. She cannot assume physical form unless she has a body, which is where the summonerRhem helps out. Deis is tired from her long slumber and first indulges in a hedonistic eating and drinking spree that leaves her tired. She passes out and the party has to revisit her on the following day.
Ryu, Nina and the others talk to the Abbess in order to revisit the dream sequence inside Ershin's mind. This time, the terrain has changed and they need to head into the innermost again in order to meet with the goddess. They meet her inside a temple, surrounded by a harem of men that seem to deify her and shower her with compliments. She is visibly displeased by the party's arrival, finding it rude to sneak into other people's dreams.
Nonetheless, she proceeds to talk to the party and explains how the Endless were summoned into the world by the Fou Empire. Basically, beings known as Endless are inhabitants of other worlds that are ripped out of these by the Spell of Evocation. In the world of Breath of Fire IV, they are revered as gods, regardless of whether they actually want this or not. Over the course of time, they fulfill their purpose and turn into dragons. She states that the nearby Yorae Shrine has the answers they are looking for, so the party proceeds to said shrine, the origin of all summons.