M_BH − M_* plane at z = 0, 1, 3, 5. Different colours represent different populations. The results have been compared with the z ∼ 0 sample of Erwin & Gadotti (2012) (squares) Reines & Volonteri (2015) (diamonds) and Capuzzo-Dolcetta & Tosta e Melo (2017) (circles), Ferré-Mateu et al. (2021) (pentagons) and Ramsden et al. (2026) (crosses). The z = 1 and z = 3 results presents the observational sample of Suh et al. (2020) (triangles) and the overmassive MBHs of Mezcua et al. (2023, 2024), respectively. The z = 5 results are compared with Maiolino et al. (2024) (circles), Harikane et al. (2023) (squares), Ding et al. (2023) (stars) and Lupi et al. (2024) (pentagons). At this redshift, the black (grey) points correspond to z ≥ 5 (z ≤ 5). The horizontal line highlights ≤10⁴ M_⊙, a mass range where electromagnetic information about the central MBH of the galaxy is expected to be undetectable by current observational facilities.