Here is my personal ranking of the five characters in Castlevania: Grimoire of Souls. You may prefer one over the others based on your personal preferences.

Alucard is the most balanced character. He is a well-rounded in air and ground attack, has high agility and mobility. Moreover, his unique equipment perks provide up to 40% attack boost, he has fast and smooth attacks animations. Additionally, in chapter 6 and 7, both bosses are weak against fire and holy element respectively, which give Alucard the advantage of his weapons that are mainly fire and holy based. 

Pros:

• Alucard’s Sword and Alucard’s Shield provides 40% attack boost.
• Fast attack speed.
• Wing Smash provides high mobility.
• Balance between air and ground attacks.
• Has strong holy and fire element (3 holy element and 3 fire element swords), effective against Camila and Death.

Cons:

• Short range melee attack.
• Slow dash attack (dash attack can stun an enemy).

FUN FACT: "Alucard" spells backward is "Dracula".

The reason Charlotte is in the second place in my list is because of her long-range attack. To balance her OP range, developers decided to nerf her attack damage, but it still doesn’t stop her becoming the fastest stage clearing character. She is the most effective in clearing stage challenges and Season Orders.

Pros: 

• Long range attack.
• Very high mobility due to her Flight skill.
• Very fast at clearing stages.
• Her healing skill with her Flight in combination of long-range attack allowing her to smash through Season Order easily without any problem.

Cons:

• Low attack damage; about ½ of normal damage.
• Hard to shoot small and close enemies.
• All character skills are useless.
• Normal attacks cannot stun enemies.

Shanoa specializes in aerial attacks. She has two different moves depending on what weapon she equipped. Her aerial moves allow her to stay in air longer and deal more damage than ground moves. Not to mention her Magnes that gives her high mobility.

Pros: 

• Very strong aerial attacks.
• Has two different attack-move sets depending on her weapon.
• Overpowered weapon skills and with her unique armor perk (30% skill damage boost) make her weapon skills even deadlier.
• Magnes (character skill) provides high mobility.

Cons:

• Short range melee attack.
• Weak ground attacks.

Simon has strength in his disposal. What he lacks are agility and mobility which make him vulnerable during his attack or skill animations. Despite his slow attacks, he has a good range of attack considering he is a melee user.

Pros:

• High damage attack.
• Balance air and ground attack.
• Long melee attack that can easily hit multiple enemies and can hit enemies from a distance.

Cons:

• Slow attack.
• Most of weapon skills are vulnerable to enemy’s attack because of the skill animation; basically, you cannot move while using skills. 

Well, I honestly hate to put her last since she has potential and fun to play. She has few problems with her attack moves. First, her aerial attacks suck, or I would say the worst, basically it is very hard to kill flying enemies. Second, her attacks barely trigger stun allowing the enemies to have time to attack her back. 

Pros: 

• Long range attack, but not as long as Charlotte.
• Smaller hit box allowing her to dodge some of the traps without crouching.
• Can run while attacking.  

Cons:

• Her attacks take forever to stun enemies.
• Worst aerial attacks.