Isobel Veloise is a new companion introduced with the High Isle Chapter. Companions are NPCs that follow the player around and support them in combat. These companions start pretty much at zero though, which means they need to be leveled.
Isobel, one of the companions, can have 20 base levels, also called Combat Levels. In order to reach the maximum level and efficiency, Isobel must level through combat. She can not receive experience by fulfilling quests, or receiving rewards otherwise.
Isobel levels almost the same as the player, except for receiving only 15% of the experience that the player gained. This means that players get the full experience and Ember gets an additional 15% of the experience that the player gained. So there’s no loss for the player. This applies only to experience gained directly from combat. Experience increasing effects such as holiday bonuses and consumable boosters applied to a player’s character will provide an indirect benefit to the companion as well.
In order to level the Fighters Guild, Mages Guild and Undaunted for Isobel, you need to do the Dailies of those guilds. Collecting Mages Guild books for example won’t level her skill line.
Isobel has to be active at all times during these activities, if the player wants to level her up. With the exception of quests and rapport, which collectively represents the relationship between each character and Isobel Veloise, all companion progress is account-wide. Meaning that when the player has Level 14 on their companion’s Combat Level, this is account-wide.
As Isobel gains combat levels, her health and overall power (which affects weapon and spell damage) increases automatically, additional ability bar slots unlock, and more class abilities become available. This includes an Ultimate slot and ability, which unlock at combat level 20.