Harry Potter and the Heroes of Old Challenge

This is a challenge requiring a crossover with the Fate Series from the Type-Moon franchise and the Harry Potter chronicles. What would happen if a young Harry/Female Harry somehow got his/her hands on a Summoning ritual for servants and managed to summon a hero from the ancient past? Naturally, the hero would clearly protest about how his/her little master is treated by his or her relatives and the Dursley family along with others who would take advantage of Harry/Female Harry would learn quickly.

Requirements for the story

- Harry can be a boy or a girl at your preference, but there cannot be a sudden magical sex change like potion or anything like. He/she must be born with the sex favored by the writer.

- The Servant summoned must be Iskander or another servant from the Fourth and Fifth Wars. I just chose Iskander because I like the guy.

- The servant teaches his/her Master how to use their time's magic that cannot be picked by the Ministry of Magic's detectors.

- Neglectful to abusive Dursleys.

- Animagus Transformation. Choice of which animal is up to the writer.

- The servant must eventually take a parental role in Harry/Female Harry's life.

- Harry/Female Harry must summon his/her servant a few years before his/her acceptance to Hogwarts.

- Find a way to get rid of the Horcrux behind Harry/Female Harry's scar without having him/her commit suicide.

- Set after the Fourth War. In case the writer chooses Iskander, he remembers his interactions with Waver and introduces Harry/Female Harry to Waver.

Elements in the story that are forbidden

- Dursleys that are nice to Harry/Female Harry.

- Harry/Fem Harry getting taken away by Social Services.

- Excessive bashing of singular characters, just because Dark Lords have come from the Slytherin House doesn't mean they are all going to be Dark Wizards.

- Yaoi.

- Harry/Female Harry being Lord/Lady of a bunch of Ancients and Nobles Houses, thus being the richest Wizard/Witch in Europe. Only houses he/she are allowed to be a part of is the Ancient and Noble House of Black since he/she is Sirius' heir until he gets a child and the Potter house is descended from the Black family or the Noble House of Potter since it is her birth family.

- Being a descendant of the Hogwarts Founders and/or Merlin. Other famous figures are allowed like Arturia or Cu Chulainn. No demigod status.

Ideas that are allowed but not strictly needed

- Harry/Female Harry going to another magic school instead of Hogwarts. Preferable if you make your own magic school like Sakurademonalchemist's Avalon Academy for Magic.

- The servant summoned being hired as Professor to be able to follow his/her 'Master'.

- Harry/Female Harry reviving the Marauders under a non-bullying policy.

Optional

- Harry/Female Harry having some form of creature inheritance.

- Harry/Female Harry coming into contact with Zelretch and initiating a prank war.

- Harry/Female Harry having a Reality Marble.

- Summoning multiples Servants.

- Harem pairings. (If male)

Have fun with that.