I have decided to write two different stories. One with the Pawn and the other with the Knight, with the protagonist of both stories being Ichigo Kurosaki.
Both stories start out the same with the introduction of an original character named Lucius Smith, who is actually the God of Hope (for more information about this character, read Chapter 2), however he will only have a minor role in the story and will only appear in the first or first two chapters. What you should know about this character, is that he has a special ability called King Authority which has the power to create a total of 15 Divine Pieces that have the ability to transform the user into a God and give them various abilities depending on the Piece used on them (for more information about how Divine Pieces work, read Chapter 3).
Original ideas:
Bishop and Twilight Healing.
Ichigo will recover energy five times as fast as normal, due to the abilities granted by the Bishop piece. In addition to that, he will have a Sacred Gear that can heal himself and others, regardless of their species. In balance breaker it surrounds the user in a aura of healing, that can heal his physical body from almost all injuries (even decapitation), this ability is known as Twilight Phoenix. However if he is in that state, he can only heal himself and his soul could still be injured.
This choice means that his fighting style relies mostly on magic.
Knight and Blade Blacksmith.
Ichigo will have the ability to use Flash Step, due to the abilities granted by the Knight piece. In addition to that, he will have a Sacred Gear which can create a specific holy sword or a pair of swords. The balance breaker is unknown as of yet and will depend on the nature of the sword(s). His Sacred Gear will differ from the Blade Blacksmith used in DxD canon, due to being much stronger and limited to one or two swords, that have a unique special ability similar to that of a Zanpakutō. This could most likely be due to the influence of his former shinigami powers, however it could also be the fanon ability of the Sacred Gear. In addition to that, he can only create one or two (if he is a dual wielder) swords at the time. Due to completely losing his shinigami, hollow and quincy powers after the use of the Final Getsuga Tenshō, the potential spirit(s) or inner world (if he has any at all) may completely differ from the one he previously had.
This choice means that his fighting style relies mostly on swordsmanship.
Rook and Twice Critical.
Ichigo will have ten times stronger durability than that of a normal human, due to the abilities granted by the Rook piece. In addition to that, he will have a Sacred Gear that hosts a dragon inside it. The Sacred Gear (also known as the Seed of the Dragon) has the ability to double the users power, such as speed, strength, durability and overall energy output. It takes the form of a black gauntlet that manifests on the user's left arm. In balance breaker, it takes the form of a black Scale Mail that has the same durability as that of the dragon inside the Sacred Gear. The reason why the dragon has not managed to make contact with Ichigo during the past year is due to having been weak, with him having only recently awakened. After all, the dragon inside Twice Critical is only as strong as the user (due to having the ability to double the users power in its base form) and hollow powers (which are considered dark or demonic) could have suppressed his Sacred Gear, that by nature is an holy item.
This choice means that his fighting style relies mostly on close combat martial arts.
Pawn without a Sacred Gear.
Ichigo will have no Sacred Gear, but he will have the abilities granted by the Pawn piece, such as Recovery of the Bishop, Flash Step of the Knight and Reinforcement of the Rook, however he can only use one ability at the time and he can not use magic while one of the abilities is activated.
This choice means that his fighting style is very versatile, but at the same time limited.
The complete list of abilities for all Divine Pieces are further explained in Chapter 3: Divine Pieces.
Authors notes:
The abilities of both Blade Blacksmith and Twice Critical differ from those of canon. The reason for that, is that in canon their abilities were rather weak.
Beings who are reincarnated by the Divine Pieces are real Gods and are completely independent, meaning that they can not be controlled by anyone (including the God of Hope), neither do they need to ask for his permission to use their abilities. Also, the user of the King Authority is not a King and despite having the power to reincarnate other beings into Gods, they are not members of his Peerage. This is the reason why this ability is named the King Authority. Authority is the power or right to give orders, make decisions, and enforce obedience. Usually it is a right given to the user by someone (in this case Chaos). Basically, it is the power to decide who should be made into a God.