For First Generation Dragon Slayers, those who have been taught their Magic by a real dragon, certain conditions must be met in order to achieve Dragon Force state: the only one known so far would be to eat substances with powerful Magical properties,[10] preferably those somehow related to the element they can control and consume; while other, unrelated substances can be eaten as well, these have been described as being similar to "poison" for the user, causing heavy after effects, such as pain on activation[11] and extreme exhaustion after use.[12] However, it is likely that, due to it being considered the final state a Dragon Slayer can achieve, Dragon Force may eventually be attained without outside sources of power. So far, Natsu Dragneel is the only Old-Style Dragon Slayer to have achieved such condition, doing so on two occasions: the first through the consumption of Etherion,[10] and the second from Jellal Fernandes' Flame of Rebuke.[13]
For 2nd Generation Dragon Slayers, those who have obtained their powers by implanting Dragon Lacrima in their body, Dragon Force mode is seemingly entered whenever they make use of their Dragon Slayer Magic.[3] However, due to this easiness to achieve this form, their powers don't seem to be increased at the same level of Old-Style Dragon Slayers, with no dragon-like aura appearing for them.[2] Laxus Dreyar and Cobra have been shown achieving such state.[2][3]
Third Generation Dragon Slayers, those who have not only been taught by a Dragon but have had Dragon Lacrima implanted into their body, are capable of activating Dragon Force whenever they choose.[14]