Within the hierarchical assembly, massive galaxies are seen to increase their size (from red nuggets to the large galaxies in the local universe), but due to the stochastic nature of mergers, some red nuggets can be seen also in the present universe, these are actually the relic galaxies. Observations find some discrepancies in the numerical abundances at low-z, but it's difficult to quantify the evolution from an in-homogeneous sample of galaxies from different surveys. Thus, to study these discrepancies and analyze the evolution with redshift of the abundance of such objects we have studied the evolution of the most compact and massive, and passive galaxies using EAGLE and C-EAGLE. Our main aim is to study the evolution with redshift and the role of the environment. EAGLE suite of hydro-simulations is the state-of-the-art numerical reproduction of the cosmic history of the Universe. C-EAGLE on the other hand is an independent hydro-simulation, based on EAGLE, concentrating on exploring the clusters and their environment. We use EAGLE and C-EAGLE to predict the number of the most compact among the most massive galaxies particularly the so-called Ultra-compact massive galaxies(UCMGs) with effective radiusRe<1.5 kpc and stellar mass>8×10^10Msun(accordingly to Trujillo et al. 2009 and Tortora et al. 2018). These predictions are compared with abundances of UCMGs in galaxies and clusters in KiDS. We show the results for 333 sq. deg. of the survey, and investigate the trend of abundances with redshift (at z <0.5). We have cross-matched with the catalogs of UCMGs to find the abundances of UCMGs in clusters. We compared: (1)abundances derived in the whole 333 sq. deg. of KiDS with abundances in EAGLE reference simulation (100 cMpc); and (2) abundances in KiDS clusters with abundances in C-EAGLE(29 clusters in Bah ́e et al. 2017). We selected all the UCMGs (using Recalculated with mass particles), counted them in redshift bins, and the number in each redshift bin is divided by the comoving volume of the ...