There are two types of Characters in Divinity; The Main Character: Who is the person you play as, and Non-Playable Characters (NPCs): Who are people in the game that you cannot control. You can talk to some of these characters, and depending on your dialog choices, they can open up quests and lead to experience or items as rewards.
At the left of the dialog it may also be possible to mindread the character to learn addition information.
Continuing with an Existing Character Edit
If you want to continue your adventure with an existing character, all you have to do is load a save game from Divinity II: Ego Draconis* and proceed to the end of the game. After the finale, Flames of Vengeance will automatically begin.
*Game saves from the original version of Divinity II: Ego Draconis are not compatible with Divinity II: The Dragon Knight Saga, due to various changes that have been brought to Ego Draconis in this version of Dragon Knight Saga.
Starting with a New Character Edit
When you want to start playing Flames of Vengeance with a new character, you will have the option of choosing either a preset or a custom hero after having selected his/her looks. This will be a level 35 character that begins the new journey with an ample amount of gold to compensate for the lack of previously acquired gear.
“Preset” means that you take you pick from among four developer-designed classes. These are: the Warrior, a melee specialist; the Mage, a magic specialist; the Ranger, a ranged specialist and the Priest, a summoning specialist. Choosing any one of these will skip all further customization and immediately trigger the start of Flames of Vengeance.
Alternatively, you can opt for Advanced Customization during which you build a brand new, level 35 character from the ground up. You can also however, still select one of the presets which you can then tweak and adjust as you see fit. It is important to note that when choosing skills during this process of character creation, you can maximize the ones you like here and now, but when starting the game the rest will have their normal skill caps again. Your skill trainers can remedy that of course!