When a quest giver makes a request to the adventurers guild the guild will assess the difficulty of the quest. Simple easy tasks such as killing a few rats in a tavern basement or gathering herbs in an open field would be considered F-rank. These quests pose almost no risk and are therefore ideal for inexperienced adventurers. That being the case, the pay is very low. E-ranked quests are more dangerous and often involve some level of combat. a typical E-ranked quest might be to slay 4 goblins in a nearby forest in order to keep them from becoming overpopulated. Escorting a merchant caravan would also be considered an E-ranked quest if the route is not particularly dangerous. Attacks by monsters or bandits are a possibility, but unlikely. D-ranked quests may involve more difficult combat challenges and a wider scope to the request itself. A village suffering repeated goblin attacks may submit a D-ranked request with the broad objective of saving the village from the goblin invasion. Successful completion may involve not only defending against an initial attack by the goblin raiding parties, but also following up by locating the goblin camp and eliminating the threat. At this rank quests may explicitly involve fighting more powerful enemies like bandits and orcs. It is unlikely but there is always the possibility of enemies slightly more powerful then this appearing, but defeating such higher ranked enemies is not required to complete the quest. C-ranked quests are for greater threats reserved for truly heroic adventurers. Countries may post a C-ranked quest to stop an invading army or slay a young dragon. Planar creatures like demons or elementals may need to be dealt with. It is possible, though unlikely that some greater threat may be encountered such as a Litch. B-ranked quests are often unreasonable, but there exist adventurers capable of rising to the challenge. A B-ranked quest may be posted asking adventurers of great skill to singlehandedly defeat the entire military of a country to win a war. Stopping a demonic invasion would also fall into this category. Slaying legendary creatures like litches, beholders, adult dragons, or destroying a colony of mind flayers would not be unusual. It is possible that such a quest may require actually traveling to another plane such as the shadowfell, abyss, or the 9 hells. A-ranked quests require legendary heroes or demigods to complete. Descending into the 9 hells and slaying an arch-devil would be considered a normal A-ranked quest. A quest to kill a god would be S-ranked. The challenges of S-ranked quest may seem near impossible, but the adventurers guild does accept such requests if the quest giver is able to pay the necessary contract fees and adventurers capable of completing them do exist. That said, it is hard to imagine anyone who could afford to pay an appropriate quest reward for such a task.