Well, in some fanfictions, he learns a spell called 'Shield of the Ancients'. This spell not only creates a strong physical shield but also protects from mental attacks. It's really useful in battle as it can block various types of dark magic. Harry has to master the complex incantation and wand movement for this spell.
One of the interesting spells could be 'Tempestus Ignis' which creates a fiery storm in some fanfictions. It gives him a powerful offensive move against dark creatures.
Chapter 228, "Justified Campaign, The Infiltration Unveiled (Part 2)", is the clearest early answer because it turns Great Xia's situation into a concrete plot event. The chapter turns that into something concrete by moving from Zhaoyang is not anything good, and neither is Great Xia, but both... to Lu Sheng continued to walk until he was less than five meters away,....
Chapter 327, "Beast Tide Showdown, the Wolf King’s Gambit, and White Dew Gu’s Last Stand", is the clearest early answer because it turns Advanced Frost Wolves's situation into a concrete plot event. The chapter turns that into something concrete by moving from Roar....." The Thunder Kui first let out an angry roar, looking like... to This mere three-digit Beast Tide, not to mention defeat, lacks any....
Chapter 272, "Disappointment and Surprise, Surge in Cold Resistance Level Participants", is the clearest early answer because Chen Ying finally turns buildup into a real advancement. It opens with Second Year of Great Xia, June 2, Late Night Xia City is still... and closes on Including Li Baihe and the others, Luo Ming naturally dared not voice....
Chapter 274, "Weakness and Power, the Final Battle Begins", is the clearest early answer because the buildup finally cashes out in a real clash. Early on, On the outskirts of Redwood Ridge, a five-hundred-meter square area.... By the end, Their emotions at this moment were evidently more excited than others.... Inside the broader family politics storyline, the danger stops being abstract and the conflict around Luo Yuan becomes immediate, forcing the surrounding cast to react under pressure.
Chapter 272, "Disappointment and Surprise, Surge in Cold Resistance Level Participants", is the clearest early answer because Shang Ping finally turns buildup into a real advancement. A useful checkpoint is the way the scene starts with Second Year of Great Xia, June 2, Late Night Xia City is still... and follows through with It was just the latter three matches where opponents were tougher;....
Chapter 243, "Hanqiong's Great Battle, Realization After the Fact (Part 2)", is the clearest early answer because the buildup finally cashes out in a real clash. The chapter turns that into something concrete by moving from Xia Hong surveyed the houses inside Hanqiong Station, marveling at... to There's an enemy attack, hide quickly." "It's real, someone's....
Chapter 267, "Stunned, the Astonishing Zhao Yuankong", is the clearest early answer because it turns Snow Mane's situation into a concrete plot event. The setup is It's not just Xiao Hen who thinks this way., but the pressure keeps building through Liu Peng, all members of group 52, and most people in the square, are.... Once the chapter lands on After scattering the crowd, it remained agile;
Chapter 298, "Hou Jing Surrenders, White Abyss Falls, Zhaoyang Changes Allegiance (Part 5)", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. The chapter turns that into something concrete by moving from Is the height of Beimang Mountain three to four times that of Twin... to By then, with Mang Mountain to the north, Xing River to the south,....
Chapter 267, "Stunned, the Astonishing Zhao Yuankong", is the clearest early answer because it turns Astonishing Zhao Yuankong's situation into a concrete plot event. A useful checkpoint is the way the scene starts with It's not just Xiao Hen who thinks this way. and follows through with Two bodies were pierced by the Snow Mane's two forest-white tusks.. By the close, After scattering the crowd, it remained agile;
Chapter 284, "Astonishing Training Results, the Peepers", is the clearest early answer because it turns Iron Arrows's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Second Year of Great Xia, June 25 Snowy night, west of Wushuang,... and follows through with Of course, their eyes still brimmed with greed as they looked at the....